U.S. patent application number 15/522881 was filed with the patent office on 2017-11-23 for display device and display control method.
This patent application is currently assigned to Sony Corporation. The applicant listed for this patent is Sony Corporation. Invention is credited to Takeo Arai, Masatake Hayashi, Motohiro Kobayashi.
Application Number | 20170336626 15/522881 |
Document ID | / |
Family ID | 55909241 |
Filed Date | 2017-11-23 |
United States Patent
Application |
20170336626 |
Kind Code |
A1 |
Hayashi; Masatake ; et
al. |
November 23, 2017 |
DISPLAY DEVICE AND DISPLAY CONTROL METHOD
Abstract
[Object] To provide display that is more favorable to a user.
[Solution] Provided is a display device including: a pixel array;
and a microlens array provided on a display surface side of the
pixel array and having lenses arranged at a pitch larger than a
pixel pitch of the pixel array. The microlens array is arranged so
that each lens of the microlens array generates a virtual image of
display of the pixel array on a side opposite to a display surface
of the pixel array, and light emitted from each lens of the
microlens array is controlled so that pictures visually recognized
through lenses of the microlens array become a continuous and
integral display by controlling the light from each pixel of the
pixel array.
Inventors: |
Hayashi; Masatake;
(Kanagawa, JP) ; Arai; Takeo; (Aichi, JP) ;
Kobayashi; Motohiro; (Kanagawa, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sony Corporation |
Tokyo |
|
JP |
|
|
Assignee: |
Sony Corporation
Tokyo
JP
|
Family ID: |
55909241 |
Appl. No.: |
15/522881 |
Filed: |
November 6, 2015 |
PCT Filed: |
November 6, 2015 |
PCT NO: |
PCT/JP2015/081406 |
371 Date: |
April 28, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02B 27/0093 20130101;
G02B 27/0081 20130101; G02B 27/1066 20130101; G02B 3/0062 20130101;
G02B 30/27 20200101; G02C 7/025 20130101; G02B 3/0056 20130101;
G02B 27/0172 20130101 |
International
Class: |
G02B 27/00 20060101
G02B027/00; G02B 27/10 20060101 G02B027/10; G02B 27/01 20060101
G02B027/01; G02C 7/02 20060101 G02C007/02; G02B 3/00 20060101
G02B003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 7, 2014 |
JP |
2014-227279 |
Jan 30, 2015 |
JP |
2015-016622 |
Claims
1. A display device comprising: a pixel array; and a microlens
array provided on a display surface side of the pixel array and
having lenses arranged at a pitch larger than a pixel pitch of the
pixel array, wherein the microlens array is arranged so that each
lens of the microlens array generates a virtual image of display of
the pixel array on a side opposite to a display surface of the
pixel array, and light emitted from each lens of the microlens
array is controlled so that pictures visually recognized through
lenses of the microlens array become a continuous and integral
display by controlling the light from each pixel of the pixel
array.
2. The display device according to claim 1, wherein an irradiation
state of light emitted from each lens of the microlens array is
periodically iterated in units larger than a maximum pupil diameter
of a user.
3. The display device according to claim 2, wherein an iteration
cycle of the irradiation state of the light is larger than a pupil
distance of the user.
4. The display device according to claim 2, wherein a value
obtained by multiplying an iteration cycle of the irradiation state
of the light by an integer is substantially equal to a pupil
distance of the user.
5. The display device according to claim 2, wherein light emitted
from each lens of the microlens array is controlled so that a pupil
of the user is not located on a boundary of iteration of the
irradiation state of the light in accordance with a position of the
pupil of the user.
6. The display device according to claim 1, wherein each lens of
the microlens array includes a telephoto type lens system in which
a convex lens and a concave lens are combined.
7. The display device according to claim 1, further comprising: a
movable mechanism configured to make a distance between the pixel
array and the microlens array variable.
8. The display device according to claim 1, wherein light emitted
from each lens of the microlens array is controlled so that a
picture captured by an imaging device is visually recognized as an
integral display through each lens of the microlens array.
9. The display device according to claim 1, wherein the pixel array
includes a plurality of printed pixels.
10. The display device according to claim 1, wherein each lens of
the microlens array has a surface shape differing in accordance
with a position of the lens within an array surface.
11. The display device according to claim 1, wherein the microlens
array is configured by stacking a plurality of microlens array
surfaces, and one microlens array surface and at least one other
microlens array surface among the plurality of microlens array
surfaces are formed so that boundary positions between lenses
within surfaces horizontal to the array surfaces are different from
each other.
12. The display device according to claim 1, wherein the microlens
array is configured by stacking a plurality of microlens array
surfaces, and one microlens array surface and at least one other
microlens array surface among the plurality of microlens array
surfaces are formed so that a plurality of lenses in the at least
one other microlens array correspond to one lens of the one
microlens array surface.
13. The display device according to claim 10, wherein each lens of
the microlens array has an aspheric shape.
14. The display device according to claim 10, wherein each lens of
the microlens array is designed so that display is unclear at a
position of a predetermined viewpoint of a user.
15. The display device according to claim 1, wherein the display
device is used as an in-vehicle display device on which driving
support information is displayed.
16. A display control method comprising: controlling light emitted
from each lens of a microlens array so that pictures visually
recognized through lenses of the microlens array become a
continuous and integral display by controlling light from each
pixel of a pixel array, the microlens array being provided on a
display surface side of the pixel array and having lenses arranged
at a pitch larger than a pixel pitch of the pixel array, wherein
the microlens array is arranged so that each lens of the microlens
array generates a virtual image of display of the pixel array on a
side opposite to a display surface of the pixel array.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to a display device and a
display control method.
BACKGROUND ART
[0002] For display devices, increasing an amount of information to
be displayed on a screen is an important mission. In view of this,
in recent years, display devices capable of performing display with
higher resolution such as, for example, 4K television, have been
developed. Particularly, in a device having a relatively small
display screen size such as a mobile device, higher-definition
display is required to display more information on a small
screen.
[0003] However, in addition to increasing the amount of information
to be displayed on the display device, high visibility is also
required. Even if higher-resolution display is performed, a degree
of resolution to which display can be determined depending on the
visual acuity of an observer (user). In particular, it is assumed
that it is difficult for elderly users to visually recognize
high-resolution displays due to presbyopia with aging.
[0004] Generally, as countermeasures against presbyopia, optical
compensation instruments such as presbyopic glasses are used.
However, because far visual acuity is degraded while presbyopic
glasses are worn, attachment/detachment is necessary in accordance
with a situation. Also, it is necessary to carry a tool for storing
presbyopic glasses such as an eyeglass case in accordance with the
necessity of attachment/detachment. For example, it is necessary
for a user with presbyopia who uses a mobile device to carry a tool
having a volume equal to or larger than that of the mobile device,
so that portability, which is an advantage of the mobile device, is
impaired, which feels annoying to many users. Furthermore, many
users feel resistance to wearing presbyopic glasses themselves.
[0005] Therefore, in a display device, particularly, a display
device having a relatively small display screen mounted on a mobile
device, technology in which the display device itself improves
visibility for a user without using additional devices such as
presbyopic glasses is desired. For example, in Patent Literature 1,
technology in which a plurality of lenses are arranged so that
images of pixel groups are overlapped and projected in a display
device including the plurality of lenses and a plurality of light
emission point (pixel) groups and the projected images from the
plurality of lenses are formed on the retina of a user by causing
an overlap of pixels in the pixel groups projected and overlapped
by the lenses to be incident on a user's pupil is disclosed. In the
technology described in Patent Literature 1, an image with a deep
focal depth is formed on the retina by adjusting a projection size
of light from a pixel on the pupil to a size smaller than a pupil
diameter and a user with presbyopia can also obtain an in-focus
image.
CITATION LIST
Patent Literature
[0006] Patent Literature 1: JP 2011-191595A
DISCLOSURE OF INVENTION
Technical Problem
[0007] However, in the technology described in Patent Literature 1,
in principle, when two or more light beams corresponding to the
overlap of pixels in the pixel groups projected and overlapped by
the lenses are incident on the pupil, the image on the retina will
be blurred. Accordingly, in the technology described in Patent
Literature 1, adjustment is performed so that an interval between
light beams corresponding to the overlap of the pixels on the pupil
(that is, projected images on the pupil of light from the pixels)
is set to be larger than the pupil diameter and a plurality of
light beams are not incident simultaneously.
[0008] However, in this configuration, when a position of the pupil
has moved with respect to the lens, there is a moment when the
light beam is not incident on the pupil. While the light beam is
not incident on the pupil, no image is visually recognized by the
user and the user can observe an invisible region such as a black
frame. Because the invisible region is periodically generated every
time the pupil moves by about the pupil diameter, it cannot be said
that comfortable display is provided for the user.
[0009] Therefore, the present disclosure provides a novel and
improved display device and display control method capable of
providing display that is more favorable to a user.
Solution to Problem
[0010] According to the present disclosure, there is provided a
display device including: a pixel array; and a microlens array
provided on a display surface side of the pixel array and having
lenses arranged at a pitch larger than a pixel pitch of the pixel
array. The microlens array is arranged so that each lens of the
microlens array generates a virtual image of display of the pixel
array on a side opposite to a display surface of the pixel array,
and light emitted from each lens of the microlens array is
controlled so that pictures visually recognized through lenses of
the microlens array become a continuous and integral display by
controlling the light from each pixel of the pixel array.
[0011] According to the present disclosure, there is provided a
display control method including: controlling light emitted from
each lens of a microlens array so that pictures visually recognized
through lenses of the microlens array become a continuous and
integral display by controlling light from each pixel of a pixel
array, the microlens array being provided on a display surface side
of the pixel array and having lenses arranged at a pitch larger
than a pixel pitch of the pixel array. The microlens array is
arranged so that each lens of the microlens array generates a
virtual image of display of the pixel array on a side opposite to a
display surface of the pixel array.
[0012] According to the present disclosure, a picture on a pixel
array resolved by each lens of a microlens array is provided as a
continuous and integral display to a user. Accordingly, it is
possible to perform display for compensating for the visual acuity
of the user without generating an invisible region as in the
technology described in Patent Literature 1. Also, because
resolution is not performed by light-ray reproduction, for example,
a pixel size of a pixel array can be increased, a degree of freedom
of design can be improved, and manufacturing costs can be
decreased.
Advantageous Effects of Invention
[0013] According to the present disclosure as described above,
display that is more favorable to a user can be provided. Note that
the effects described above are not necessarily limitative. With or
in the place of the above effects, there may be achieved any one of
the effects described in this specification or other effects that
may be grasped from this specification.
BRIEF DESCRIPTION OF DRAWINGS
[0014] FIG. 1 is a graph illustrating an example of relationships
between limit resolution and visual acuity and a viewing
distance.
[0015] FIG. 2 is a graph illustrating an example of relationships
between a limit resolution of a user with emmetropia and an age and
a viewing distance.
[0016] FIG. 3 is a graph illustrating an example of relationships
between a limit resolution of a user with myopia and an age and a
viewing distance.
[0017] FIG. 4 is an explanatory diagram illustrating a concept for
assigning depth information to two-dimensional picture
information.
[0018] FIG. 5 is a diagram illustrating an example of a
configuration of a light-ray reproduction display device.
[0019] FIG. 6 is a diagram illustrating an example of a
configuration of a display device that displays a general
two-dimensional picture.
[0020] FIG. 7 is a schematic diagram illustrating a state in which
a user's focus is aligned with a display surface in a general
two-dimensional display device.
[0021] FIG. 8 is a schematic diagram illustrating a state in which
the user's focus is not aligned with the display surface in the
general two-dimensional display device.
[0022] FIG. 9 is a schematic diagram illustrating a relationship
between a virtual image surface in the light-ray reproduction
display device and an image formation surface on a retina of the
user.
[0023] FIG. 10 is a diagram illustrating an example of a
configuration of a display device according to a first
embodiment.
[0024] FIG. 11 is a diagram illustrating a light ray emitted from a
microlens in a normal mode.
[0025] FIG. 12 is a diagram illustrating a specific display example
of a pixel array in the normal mode.
[0026] FIG. 13 is a diagram illustrating a positional relationship
between a virtual image surface and a display surface of a
microlens array in the normal mode.
[0027] FIG. 14 is a diagram illustrating a light ray emitted from a
microlens in a visual acuity compensation mode.
[0028] FIG. 15 is a diagram illustrating a specific display example
of a pixel array in the visual acuity compensation mode.
[0029] FIG. 16 is a diagram illustrating a positional relationship
between a virtual image surface and a display surface of a
microlens array in the visual acuity compensation mode.
[0030] FIG. 17 is a diagram illustrating a relationship between a
pupil diameter of a pupil of a user and a size of a sampling
region.
[0031] FIG. 18 is a diagram illustrating a relationship between
.lamda. and PD when an iteration cycle .lamda. satisfies Equation
(3).
[0032] FIG. 19 is a diagram illustrating a relationship between
.lamda. and PD when an iteration cycle .lamda. satisfies Equation
(4).
[0033] FIG. 20 is a diagram illustrating an influence of the
relationship between an iteration cycle .lamda. and PD on a size of
a continuous display region.
[0034] FIG. 21 is a flowchart illustrating an example of a
processing procedure of a display control method according to the
first embodiment.
[0035] FIG. 22 is a diagram illustrating an example of a
configuration in which a display device according to the first
embodiment is applied to a wearable device.
[0036] FIG. 23 is a diagram illustrating an example of a
configuration in which a display device according to the first
embodiment is applied to another mobile device.
[0037] FIG. 24 is a diagram illustrating an example of a general
electronic loupe device.
[0038] FIG. 25 is a schematic diagram illustrating a state of a
decrease of a pixel size dp due to a first shielding plate having a
rectangular opening (aperture).
[0039] FIG. 26 is a schematic diagram illustrating a state of a
decrease of a pixel size dp due to a first shielding plate having a
circular opening (aperture).
[0040] FIG. 27 is a diagram illustrating an example of a
configuration in which the first shielding plate is provided
between a backlight and a liquid crystal layer.
[0041] FIG. 28 is a diagram illustrating an example of a
configuration of a display device according to a modified example
in which dynamic control of an irradiation state in accordance with
pupil position detection is performed.
[0042] FIG. 29 is an explanatory diagram illustrating generation of
a virtual image in a general convex lens.
[0043] FIG. 30 is a diagram illustrating an example of a
configuration of a display device according to a second
embodiment.
[0044] FIG. 31 is a flowchart illustrating an example of a
processing procedure of a display control method according to the
second embodiment.
[0045] FIG. 32 is a diagram illustrating an example of a
configuration of a telephoto type lens system.
[0046] FIG. 33 is a diagram schematically illustrating positional
relationships between positions of two eyes of a user who observes
a display device and microlenses of a microlens array.
[0047] FIG. 34 is an explanatory diagram illustrating a method of
designing a microlens.
[0048] FIG. 35 is a diagram illustrating an example of a
configuration in which a positional relationship between
microlenses of two-layer microlens arrays is shifted in accordance
with a position of a viewpoint of a user in a microlens array
including the two-layer microlens arrays.
[0049] FIG. 36 is a diagram illustrating an example of a
configuration in which the number of microlenses mutually
corresponding to two-layer microlens arrays is changed in
accordance with a position of a viewpoint of a user in a microlens
array including the two-layer microlens arrays.
MODE(S) FOR CARRYING OUT THE INVENTION
[0050] Hereinafter, (a) preferred embodiment(s) of the present
disclosure will be described in detail with reference to the
appended drawings. In this specification and the appended drawings,
structural elements that have substantially the same function and
structure are denoted with the same reference numerals, and
iterated explanation of these structural elements is omitted.
[0051] Also, the description will be given in the following
order.
1. Background of present disclosure
2. First Embodiment
[0052] 2-1. Basic principle of first embodiment 2-2. Display device
according to first embodiment 2-2-1. Device configuration 2-2-2.
Driving example 2-2-2-1. Normal mode 2-2-2-2. Visual acuity
compensation mode 2-2-3. Detailed design 2-2-3-1. Sampling region
2-2-3-2. Iteration cycle of irradiation state of sampling region
2-3. Display control method 2-4. Application examples 2-4-1.
Application to wearable device 2-4-2. Application to other mobile
devices 2-4-3. Application to electronic loupe device 2-4-4.
Application to in-vehicle display device 2-5. Modified example
2-5-1. Decrease of pixel size in accordance with aperture 2-5-2.
Example of configuration of light emission point other than
microlens 2-5-3. Dynamic control of irradiation state in accordance
with pupil position detection 2-5-4. Modified example in which
pixel array is implemented by printing material
3. Second Embodiment
[0053] 3-1. Background of second embodiment 3-2. Device
configuration 3-3. Display control method 3-4. Modified example 4.
Configuration of microlens array
5. Supplement
1. Background of Present Disclosure
[0054] First, prior to describing a preferred embodiment of the
present disclosure, a background that the present inventors have
conceived for the present disclosure will be described.
[0055] As described above, in recent years, display devices capable
of performing display with higher resolution have been developed.
Particularly, in a device having a relatively small display screen
size such as a mobile device, higher-definition display is required
to display more information on a small screen.
[0056] However, the resolution capable of being distinguished by a
user depends on the visual acuity of the user. Accordingly, even
when a resolution beyond a limit of the visual acuity of the user
is pursued, an advantage is not necessarily given to the user.
[0057] Relationships between the resolution (limit resolution)
capable of being distinguished by a user and visual acuity and a
viewing distance (a distance between the display surface of the
display device and the pupil of the user) are illustrated in FIG.
1. FIG. 1 is a graph illustrating the relationships between the
limit resolution and the visual acuity and the viewing distance. In
FIG. 1, the viewing distance (mm) is taken on the horizontal axis,
the limit resolution (ppi: pixels per inch) is taken on the
vertical axis, and a relationship between the two is plotted. Also,
the visual acuity is taken as a parameter and the relationship
between the viewing distance and the limit resolution is plotted
for a case in which the visual acuity is 1.0 and a case in which
the visual acuity is 0.5.
[0058] Referring to FIG. 1, it can be seen that as the viewing
distance increases, that is, as the distance between the display
surface and the pupil increases, the limit resolution decreases.
Also, it can be seen that the lower the visual acuity, the lower
the resolution limit.
[0059] Here, the resolution of a product X that is generally
distributed is about 320 (ppi) (indicated by a broken line in FIG.
1). From FIG. 1, it can be seen that the resolution of the product
X is set to be slightly larger than the limit resolution at the
viewing distance 1 (foot) (=304.8 (mm)) of a user whose visual
acuity is 1.0. That is, in the product X, the resolution
effectively functions in the sense that pixels cannot be recognized
for a user having a visual acuity of 1.0 viewing the display
surface from the distance of 1 (foot).
[0060] On the other hand, visual acuity differs depending on a
user. Some users have myopia where visual acuity is degraded at a
long distance, and others have presbyopia where visual acuity is
degraded at a short distance due to aging. When considering the
relationship between the limit resolution and the resolution of the
display surface, it is also necessary to consider such a change in
the visual acuity of the user depending on the viewing distance. In
the example illustrated in FIG. 1, the limit resolution at the
viewing distance 1 (foot) of a user whose visual acuity is 0.5 is
about 150 (ppi), and only about half of the resolution of the
product X can be distinguished at the same viewing distance of 1
(foot) of the user.
[0061] A user with presbyopia is considered with reference to FIGS.
2 and 3. FIG. 2 illustrates an example in which relationships
between a limit resolution of a user with emmetropia with a
far-field visual acuity of 1.0 and an age and a viewing distance
are approximated. In FIG. 2, the viewing distance (mm) is taken on
the horizontal axis, the limit resolution (ppi) of a user with
general emmetropia is taken on the vertical axis, and a
relationship between the two is plotted. Also, when the age is
taken as a parameter and the age is 9 years old, 40 years old, 50
years old, 60 years old, and 70 years old, the relationship between
the viewing distance and the limit resolution is plotted.
[0062] Also, an example in which relationships between the limit
resolution of a user having standard myopia to the extent that a
lens of -1.0 (diopter) is appropriate for far-field vision and an
age and a viewing distance are approximated is illustrated in FIG.
3. FIG. 3 is a graph illustrating an example in which relationships
between a limit resolution of a user with myopia and an age and a
viewing distance are approximated. In FIG. 3, the viewing distance
(mm) is taken on the horizontal axis, the limit resolution (ppi) of
a general myopia user is taken on the vertical axis, and the
relationship between the two is plotted. Also, when the age is
taken as a parameter and the age is 9 years old, 40 years old, 50
years old, 60 years old, and 70 years old, a relationship between
the viewing distance and the limit resolution is plotted.
[0063] Referring to FIGS. 2 and 3, it can be seen that the limiting
resolution decreases with the age with respect to both the user
with emmetropia and the user with myopia. This is due to presbyopia
progressing with aging. In FIGS. 2 and 3, together with the
resolution of the product X illustrated in FIG. 1, the resolution
of another product Y is also shown. The resolution of the product Y
is about 180 (ppi) (indicated by a different type of broken line
from that for the product X in FIGS. 2 and 3).
[0064] From FIG. 2, it can be seen that the resolution of the
product X cannot be substantially distinguished by a user of 40
years old or more having emmetropia. Also, referring to FIG. 3, it
can be seen that, although the decrease of the limit resolution in
accordance with aging is gentle for a user with myopia compared to
a user with emmetropia, the resolution of the product X cannot be
substantially distinguished for users of 50 years old or more.
[0065] Here, referring to FIGS. 2 and 3, if the viewing distance is
around 250 (mm), for example, for a user of 40 years old, there is
a possibility of their limit resolution exceeding the resolution of
product X and it being possible to distinguish the resolution of
product X. However, the range of the viewing distance where the
limit resolution exceeds the resolution of product X is extremely
limited. The limit resolution decreases due to presbyopia when the
viewing distance becomes closer and the limit resolution decreases
due to a limit of visual acuity in accordance with a distance to
the display surface when the viewing distance becomes farther away.
It is not desirable for the user to visually recognize the display
surface in a state in which the viewing distance is always kept
within the range in terms of comfortable use.
[0066] As described above, for a user with presbyopia of, for
example, 40 years old or more, it is difficult to say that the
resolution enhancement of about 300 (ppi) or more is meaningful
from a viewpoint of the benefit to the user. However, despite the
fact that the amount of information handled by users has increased
in recent years, devices handled by users like mobile devices have
tended to become miniaturized. Accordingly, it is an inevitable
requirement to increase an information density in the display
screen in, for example, mobile devices such as smart phones and
wearable devices.
[0067] As a method of improving the visibility for the user, it is
conceivable to decrease the density of the information on the
display screen, such as increasing a character size of the display
screen. However, this method is contrary to a demand for higher
density of information. Also, if the density of the information on
the display screen decreases, the amount of information given to
the user on one screen decreases and the usability for the user
also decreases. Alternatively, it is conceivable to increase the
amount of information on one screen by increasing the size of the
display screen itself, but, in that case, portability, which is an
advantage of the mobile device, deteriorates.
[0068] While there is a demand to provide a high-resolution display
screen having a larger information density amount for all users
including the elderly as described above, there is a limit due to
the user's visual acuity in the resolution capable of being
distinguished by the user.
[0069] Here, as described above, in general, optical compensation
instruments such as presbyopic glasses are widely used as a
countermeasure against presbyopia. However, presbyopic glasses need
to be attached and detached in accordance with the distance to an
observation object. In accordance with this, it is necessary to
carry tools for storing presbyopic glasses such as eyeglass cases.
It is necessary for users using mobile devices to carry tools with
a volume equal to or larger than that of the mobile device, which
feels annoying to many users. Further, many users feel resistance
to wearing presbyopic glasses themselves.
[0070] In view of the above circumstances, there has been a demand
for technology capable of providing favorable visibility for a user
in which high-resolution display is able to be distinguished
without using additional instruments such as presbyopic glasses.
The present inventors have conceived the following embodiments of
the present disclosure as a result of diligently studying
technology capable of providing favorable visibility for a user by
devising the configuration of a display device without using
additional instruments such as presbyopic glasses.
[0071] Hereinafter, the first and second embodiments conceived by
the present inventors as preferred embodiments of the present
disclosure will be described.
2. First Embodiment
2-1. Basic Principle of First Embodiment
[0072] First, prior to describing a specific device configuration,
the basic principle of the first embodiment will be described with
reference to FIG. 4. FIG. 4 is an explanatory diagram illustrating
a concept of assigning depth information to two-dimensional picture
information.
[0073] As illustrated in the right diagram of FIG. 4, in a general
display device, picture information is displayed as a
two-dimensional picture on the display surface. Two-dimensional
picture information can be said to be picture information without
depth information.
[0074] Here, there is technology called irradiation field
photography as photographic technology capable of obtaining
pictures at various focal positions through calculation by
acquiring information about both a position and a direction of
light rays in a space of a subject without obtaining information
about the intensity of light incident from each direction as in a
normal photographing device when the subject is photographed. This
technology can be implemented by performing a process of simulating
a state of image formation within a camera through calculation on
the basis of a light-ray state within the space (light field).
[0075] On the other hand, as technology for reproducing information
of the light-ray state (light field) in a real space, technology
called light-ray reproduction technology is also known. In the
example illustrated in FIG. 4, the light-ray state in a case in
which the display surface is present at the position X is first
obtained through calculation, and the obtained light-ray state is
reproduced by the light-ray reproduction technology, so that a real
display surface is located at a position O, but it is possible to
reproduce the light-ray state as if the display surface were
located at a position X different from the position O (see the
middle drawing in FIG. 4). Information of the light-ray state
(light-ray information) can also be said to be three-dimensional
picture information in which information about the position in a
depth direction of a virtual display surface is assigned to
two-dimensional picture information.
[0076] By reproducing a light-ray state as if the display surface
were located at the position X in accordance with the light-ray
information and irradiating the user's pupil with light in the
irradiation state based on the light-ray state, the user visually
recognizes an image on a virtual display surface (that is, a
virtual image) located at the position X. If the position X is
adjusted to a position in focus for, for example, a user with
presbyopia, it is possible to provide an in-focus picture to the
user.
[0077] As such a display device for reproducing a predetermined
light-ray state on the basis of light-ray information, several
light-ray reproduction type display devices are known. The
light-ray reproduction type display device is configured so that
light from each pixel can be controlled in accordance with an
emission direction, and is widely used as, for example, a naked-eye
3D display device that provides 3D pictures by emitting light so
that a picture taking into consideration binocular parallax on left
and right eyes of the user is recognized.
[0078] An example of the configuration of the light-ray
reproduction type display device is illustrated in FIG. 5. FIG. 5
is a diagram illustrating an example of the configuration of the
light-ray reproduction type display device. Also, for comparison,
an example of a configuration of a display device that displays a
general two-dimensional picture is illustrated in FIG. 6. FIG. 6 is
a diagram illustrating an example of a configuration of a display
device that displays a general two-dimensional picture.
[0079] Referring to FIG. 6, a display surface of a general display
device 80 includes a pixel array 810 in which a plurality of pixels
811 are two-dimensionally arranged. In FIG. 6, for convenience, the
pixel array 810 is illustrated as if the pixels 811 were arranged
in one column, but, in reality, the pixels 811 are arranged also in
the depth direction of the drawing sheet. The amount of light from
each pixel 811 is not controlled depending on the emission
direction, and a controlled amount of light is similarly emitted in
any direction. The two-dimensional picture described with reference
to the drawing on the right side of FIG. 4 indicates, for example,
a two-dimensional picture displayed on the display surface 815 of
the pixel array 810 illustrated in FIG. 6. Hereinafter, in order to
distinguish it from the light-ray reproduction type display device,
a display device 80 for displaying a two-dimensional picture (that
is, picture information without depth information) as represented
in FIG. 6 is also referred to as a two-dimensional display device
80.
[0080] Referring to FIG. 5, a light-ray reproduction type display
device 15 includes a pixel array 110 in which a plurality of pixels
111 are two-dimensionally arranged and a microlens array 120
provided on a display surface 115 of the pixel array 110. In FIG.
5, for convenience, the pixel array 110 is illustrated as if the
pixels 111 were arranged in one column, but the pixels 111 are also
actually arranged in a depth direction of the drawing sheet.
Likewise, also in the microlens array 120, the microlenses 121 are
actually arranged in the depth direction of the drawing sheet.
Because the light from each pixel 111 is emitted through the
microlens 121, the lens surface 125 of the microlens array 120
becomes an apparent display surface 125 in the light-ray
reproduction type display device 15.
[0081] A pitch of the microlenses 121 in the microlens array 120 is
configured to be larger than the pitch of the pixels 111 in the
pixel array 110. That is, a plurality of pixels 111 are located
immediately below one microlens 121. Accordingly, light from the
plurality of pixels 111 is incident on one microlens 121, and is
emitted with directivity. Consequently, by appropriately
controlling the driving of each pixel 111, it is possible to adjust
a direction, a wavelength, an intensity, etc. of the light emitted
from each microlens 121.
[0082] In this manner, in the light-ray reproduction type display
device 15, each microlens 121 constitutes a light emission point,
and the light emitted from each light emission point is controlled
by a plurality of pixels 111 provided immediately below each
microlens 121. By driving each pixel 111 on the basis of the
light-ray information, the light emitted from each light emission
point is controlled and a desired light-ray state is
implemented.
[0083] Specifically, in the example illustrated in, for example,
FIG. 4, the light-ray information includes information about an
emission state of light (a direction, a wavelength, an intensity,
etc. of emitted light) in each microlens 121 for observing an image
(that is, a virtual image) on a virtual display surface located at
the position X different from the position O when the real display
surface located at the position O (corresponding to the display
surface 125 of the microlens array 120 illustrated in FIG. 5) is
viewed. Each pixel 111 is driven on the basis of the light-ray
information and light whose emission state is controlled is emitted
from each microlens 121, so that the user's pupil is irradiated
with light for observing a virtual image at the position X for the
user located at the observation position. It can also be said that
controlling the emission state of light on the basis of the
light-ray information is controlling the irradiation state of light
for the user's pupil.
[0084] The above-described details including the state of image
formation on the retina of the user will be described in more
detail with reference to FIGS. 7 to 9. FIG. 7 is a schematic
diagram illustrating a state in which the user's focus is aligned
with the display surface in the general two-dimensional display
device 80. FIG. 8 is a schematic diagram illustrating a state in
which the user's focus is not aligned with the display surface in
the general two-dimensional display device 80. FIG. 9 is a
schematic diagram illustrating a relationship between a virtual
image surface in the light-ray reproduction type display device 15
and an image formation surface on the user's retina. In FIGS. 7 to
9, the pixel array 810 and the display surface 815 of the general
two-dimensional display device 80 or the microlens array 120 and
the display surface 125 of the light-ray reproduction type display
device 15 and a lens 201 (a crystalline lens 201) and a retina 203
of an eye of the user are schematically illustrated.
[0085] Referring to FIG. 7, a state in which a picture 160 is
displayed on the display surface 815 is schematically illustrated.
In the general two-dimensional display device 80, in a state in
which the user's focus is aligned with the display surface 815,
light from each pixel 811 of the pixel array 810 passes through the
lens 201 of the user's eye and an image thereof is formed on the
retina 203 (that is, the image formation surface 204 is located on
the retina 203). Arrows drawn with different line types in FIG. 7
indicate light of different wavelengths emitted from the pixels
811, that is, light of different colors.
[0086] In FIG. 8, a state in which the display surface 815 is
located closer to the user than in the state illustrated in FIG. 7
and the user's focus is not aligned with the display surface 815 is
illustrated. Referring to FIG. 8, light from each pixel 811 of the
pixel array 810 does not form an image on the user's retina 203 and
the image formation surface 204 is located behind the retina 203.
In this case, a blurred picture out of focus is recognized by the
user. FIG. 8 illustrates a state in which a user having presbyopia
views a blurred picture in an attempt to view a nearby display
surface.
[0087] FIG. 9 illustrates a light-ray state when the light-ray
reproduction type display device 15 is driven such that it displays
a picture 160 on the virtual image surface 150 as a virtual image
for the user. In FIG. 9, similar to the display surface 815
illustrated in FIG. 8, the display surface 125 is located
relatively close to the user. The virtual image surface 150 is set
as a virtual display surface located farther away than the real
display surface 125.
[0088] Here, as described above, in the light-ray reproduction type
display device 15, an emission state of light can be controlled so
that microlenses 121 (that is, light emission points 121) emit
light of mutually different light intensities and/or wavelengths in
mutually different directions instead of isotropically emitting
unique light. For example, the light emitted from each microlens
121 is controlled so that the light from the picture 160 on the
virtual image surface 150 is reproduced. Specifically, for example,
assuming virtual pixels 151 (151a and 151b) on the virtual image
surface 150, it can be considered that light of a first wavelength
is emitted from a certain virtual pixel 151a and light of a second
wavelength is emitted from the other virtual pixel 151b in order to
display the picture 160 on the virtual image surface 150. In
accordance with this, the emission state of the light is controlled
so that the microlens 121a emits the light of the first wavelength
in the direction corresponding to the light from the pixel 151a and
emits the light of the second wavelength in the direction
corresponding to the light from the pixel 151b. Although not
illustrated, a pixel array is actually provided on the back side
(the right side of the drawing sheet in FIG. 9) of the microlens
array 120 as illustrated in FIG. 5 and driving of each pixel of the
pixel array is controlled, so that the emission state of light from
the microlens 121a is controlled.
[0089] Here, the distance from the retina 203 of the virtual image
surface 150 is set to a position in focus for the user, for
example, a position of the display surface 815 illustrated in FIG.
7. The light-ray reproduction type display device 15 is driven such
that it reproduces the light from the picture 160 on the virtual
image surface 150 located at such a position, so that the image
formation surface 204 of the light from the real display surface
125 is located behind the retina 203, but an image of the picture
160 on the virtual image surface 150 is formed on the retina 203.
Accordingly, in terms of a user having presbyopia, even when the
distance between the user and the display surface 125 is short, the
user can view a favorable picture 160 similar to that in a distant
view.
[0090] The basic principle of the first embodiment has been
described above. As described above, in the first embodiment, by
using the light-ray reproduction type display device, the light
from the picture 160 on the virtual image surface 150 which is set
at a position in focus for a user with presbyopia is reproduced and
the light is emitted to the user. This allows the user to observe
the in-focus picture 160 on the virtual image surface 150.
Accordingly, for example, even when the picture 160 is a
high-resolution picture in which the resolution at the viewing
distance on the real display surface 125 exceeds the limit
resolution of the user, the in-focus picture is provided to the
user without using additional optical compensation instruments such
as presbyopic glasses and a fine picture 160 can be observed.
Consequently, even when the density of information is increased in
a comparatively small display screen as described in the above (1.
Background of present disclosure), the user can favorably observe a
picture on which high-density information is displayed by
supplementing the visual acuity of the user. Also, according to the
first embodiment, because it is possible to perform display in
which visual acuity compensation is performed without using optical
compensation instruments such as presbyopic glasses as described
above, it is unnecessary to carry additional portable items such as
presbyopic glasses themselves and/or a glasses case for storing
presbyopic glasses and the burden on the user is decreased.
[0091] Also, although a case in which the virtual image surface 150
is set to be farther away than the real display surface 125 as
illustrated in FIG. 9 to compensate for the visual acuity for the
user with presbyopia has been described above, the first embodiment
is not limited to such an example. For example, the virtual image
surface 150 may be set to be closer than the real display surface
125. In this case, the virtual image surface 150 is set at a
position in focus for, for example, a user with myopia. Thereby,
the user with myopia can observe the in-focus picture 160 without
using optical compensation instruments such as eyeglasses and
contact lenses. Switching of display between visual acuity
compensation for a user with presbyopia and visual acuity
compensation for a user with myopia can be freely implemented
simply by changing data displayed on each pixel and it is
unnecessary to change a hardware mechanism.
2-2. Display Device According to First Embodiment
[0092] A detailed configuration of the display device according to
the first embodiment capable of implementing an operation based on
the basic principle described above will be described.
(2-2-1. Device Configuration)
[0093] The configuration of the display device according to the
first embodiment will be described with reference to FIG. 10. FIG.
10 is a diagram illustrating an example of the configuration of the
display device according to the first embodiment.
[0094] Referring to FIG. 10, the display device 10 according to the
first embodiment includes a pixel array 110 in which a plurality of
pixels 111 are two-dimensionally arranged, a microlens array 120
provided on the display surface 115 of the pixel array 110, and a
control unit 130 that controls driving of each pixel 111 of the
pixel array 110. Here, the pixel array 110 and the microlens array
120 illustrated in FIG. 10 are similar to those illustrated in FIG.
5. Also, the control unit 130 drives each pixel 111 such that it
reproduces a predetermined light-ray state on the basis of the
light-ray information. In this manner, the display device 10 can be
configured as a light-ray reproduction display device.
[0095] As in the light-ray reproduction type display device 15
described with reference to FIG. 5, the pitch of the microlenses
121 in the microlens array 120 is configured to be larger than the
pitch of the pixels 111 in the pixel array 110 and light from a
plurality of pixels 111 is incident on one microlens 121 and is
emitted with directivity. As described above, in the display device
10, each microlens 121 constitutes a light emission point. The
microlens 121 corresponds to a pixel in a general two-dimensional
display device, and the lens surface 125 of the microlens array 120
becomes an apparent display surface 125 in the display device
10.
[0096] The pixel array 110 may include a liquid crystal layer
(liquid crystal panel) of a liquid crystal display device having,
for example, a pixel pitch of about 10 (.mu.m). Although not
illustrated, various structures provided for the pixels in general
liquid crystal display devices such as a driving element for
driving each pixel of the pixel array 110 and a light source
(backlight) may be connected to the pixel array 110. However, the
first embodiment is not limited to this example and another display
device such as an organic EL display device or the like may be used
as the pixel array 110. Also, the pixel pitch is not limited to the
above example and may be appropriately designed in consideration of
the resolution etc. desired to be implemented.
[0097] The microlens array 120 is configured by two-dimensionally
arranging convex lenses having, for example, a focal length of 3.5
(mm), in a lattice form with a pitch of 0.15 (mm). The microlens
array 120 is provided to substantially cover the entire pixel array
110. A distance between the pixel array 110 and the microlens array
120 is set to be longer than the focal length of each microlens 121
of the microlens array 120 and the pixel array 110 and the
microlens array 120 are configured to be at positions at which an
image on the display surface 115 of the pixel array 110 is
approximately formed on a plane substantially parallel to the
display surface 115 (or the display surface 125) including the
user's pupil. Generally, the image formation position of the
picture on the display surface 115 can be preset as an observation
position assumed when the user observes the display surface 115.
However, the focal length and the pitch of the microlenses 121 in
the microlens array 120 are not limited to the above-described
example, and may be appropriately designed on the basis of an
arrangement relationship with other members, the image formation
position of the picture on the display surface 115 (that is, an
assumed observation position of the user), or the like.
[0098] The control unit 130 includes a processor such as a central
processing unit (CPU) or a digital signal processor (DSP) and
operates in accordance with a predetermined program, thereby
controlling the driving of each pixel 111 of the pixel array 110.
The control unit 130 has a light-ray information generating unit
131 and a pixel driving unit 132 as its functions.
[0099] The light-ray information generating unit 131 generates
light-ray information on the basis of region information, virtual
image position information, and picture information. Here, the
region information is information about a region group including a
plurality of regions which are set on a plane including the user's
pupil and substantially parallel to the display surface 125 of the
microlens array 120 and which are smaller than the pupil diameter
of the user. The region information includes information about a
distance between the plane on which the region is set and the
display surface 125, information about a size of the region, and
the like.
[0100] In FIG. 10, a plane 205 including the pupil of the user, a
plurality of regions 207 set on the plane 205, and a region group
209 are simply illustrated. The plurality of regions 207 are set to
be located in the pupil of the user. The region group 209 is set in
a range in which light emitted from each microlens 121 can reach
the plane 205. In other words, the microlens array 120 is
configured so that the region group 209 is irradiated with the
light emitted from one microlens 121.
[0101] Here, in the first embodiment, the wavelength, the
intensity, and the like of light emitted from each microlens 121
are adjusted in accordance with the combination of the microlens
121 and the region 207. That is, for each region 207, the
irradiation state of light incident on the region 207 is
controlled. The region 207 corresponds to a size in which light
from one pixel 111 is projected onto the pupil (a projection size
of light from the pixel 111 on the pupil) and an interval between
the regions 207 can be said to indicate a sampling interval when
light is incident on the pupil of the user. In the following
description, the region 207 is also referred to as a sampling
region 207. The region group 209 is also referred to as a sampling
region group 209.
[0102] The virtual image position information is information about
a position at which a virtual image is generated (a virtual image
generation position). The virtual image generation position is the
position of the virtual image surface 150 illustrated in FIG. 9.
The virtual image position information includes information about
the distance from the display surface 125 to the virtual image
generation position. Also, the picture information is
two-dimensional picture information presented to the user.
[0103] On the basis of the region information, the virtual image
position information, and the picture information, the light-ray
information generating unit 131 generates light-ray information
indicating the light-ray state for light from the picture to be
incident on each sampling region 207 based on the region
information when the picture based on the picture information is
displayed at the virtual image generation position based on the
virtual image position information. The light-ray information
includes information about the emission state of light in each
microlens 121 and information about the irradiation state of the
light for each sampling region 207 for reproducing the light-ray
state. A process to be performed by the light-ray information
generating unit 131 corresponds to a process of assigning depth
information to the two-dimensional picture information described
with reference to FIG. 4 in the above (2-1. Basic principle of
first embodiment).
[0104] Also, the picture information may be transmitted from
another device or may be pre-stored in a storage device (not shown)
provided in the display device 10. The picture information may be
information about pictures, text, graphs, and the like which
represent results of various processes executed by a general
information processing device.
[0105] Also, the virtual image position information may be input in
advance by, for example, the user, a designer of the display device
10, or the like, and stored in the above-described storage device.
Also, in the virtual image position information, the virtual image
generation position is set to be a position in focus for the user.
For example, a general focus position that is suitable for a
relatively large number of users having presbyopia may be set as a
virtual image generation position by the designer of the display
device 10 or the like. Alternatively, the virtual image generation
position may be appropriately adjusted in accordance with the
user's visual acuity by the user, and the virtual image position
information within the above-described storage device may be
updated each time.
[0106] Also, the region information may be input in advance by, for
example, the user, the designer of the display device 10, or the
like, and may be stored in the above-described storage device.
Here, the distance between the display surface 125 and a plane 205
on which the sampling region 207 is set (the plane 205 corresponds
to the observation position of the user) included in the region
information may be set on the basis of a position at which the user
is assumed to generally observe the display device 10. For example,
if a device equipped with the display device 10 is a wristwatch
type wearable device, the above-described distance can be set in
consideration of a distance between the user's pupil and an arm
that is an attachment position of the wearable device. Also, for
example, if the device equipped with the display device 10 is a
stationary type television installed in a room, the above-described
distance can be set in consideration of a general distance between
a television and a user's pupil when the television is watched.
Alternatively, the above-described distance may be appropriately
adjusted by the user in accordance with a usage mode, and the
virtual image position information in the storage device may be
updated each time. Also, the size of the sampling region 207
included in the region information can be appropriately set in
consideration of matters to be described in the following (2-2-3-1.
Sampling region).
[0107] The light-ray information generating unit 131 provides the
generated light-ray information to the pixel driving unit 132.
[0108] The pixel driving unit 132 drives each pixel 111 of the
pixel array 110 such that it reproduces the light-ray state when a
picture based on the picture information is displayed on the
virtual image surface on the basis of the light-ray information. At
this time, the pixel driving unit 132 drives each pixel 111 so that
the light emitted from each microlens 121 is controlled
independently for each sampling region 207. Thereby, as described
above, the irradiation state of light incident on the sampling
region 207 is controlled for each sampling region 207. For example,
in the example illustrated in FIG. 10, a state in which light 123
configured by superimposing light from a plurality of pixels 111 is
incident on each sampling region 207 is illustrated.
[0109] Here, the projection size of the light 123 on the pupil (on
the plane 205) needs to be equal to or less than the size of the
sampling region 207 in order to cause the light 123 to be incident
on the sampling region 207. Accordingly, in the display device 10,
the structure, arrangement, and the like of each member are
designed so that the projection size of the light 123 on the pupil
is equal to or smaller than the size of the sampling region
207.
[0110] On the other hand, as will be described in detail in the
following (2-2-3-1. Sampling region), an amount of blur of the
image on the retina of the user depends upon the projection size of
the light 123 on the pupil (that is, an entrance pupil diameter of
light). If the amount of blur on the retina is larger than the size
on the retina of an image capable of being distinguished by the
user, a blurred image will be recognized by the user. When an
adjustment function of the eye is insufficient due to presbyopia or
the like, the projection size of the light 123 on the pupil
corresponding to the size of the sampling region 207 needs to be
sufficiently smaller than the pupil diameter in order to make the
amount of blur on the retina equal to or smaller than the size on
the retina of an image capable of being distinguished by the
user.
[0111] Specifically, whereas the general human pupil diameter is
about 2 (mm) to 8 (mm), it is preferable to set the size of the
sampling region 207 to about 0.6 (mm) or less. Conditions required
for the size of the sampling region 207 will be described in detail
again in the following (2-2-3-1. Sampling region).
[0112] Here, as is apparent from FIG. 10, the projection size of
the light 123 on the pupil depends on an image magnification and a
size dp of the pixel 111 of the pixel array 110. Here, the image
magnification is a ratio between a viewing distance (a distance
between the lens surface 125 of the microlens array 120 and the
pupil) DLP and a lens inter-pixel distance (a distance between the
lens surface 125 of the microlens array 120 and the display surface
115 of the pixel array 110) DXL (DLP/DXL). Accordingly, in the
first embodiment, the size dp of the pixel 111, the arrangement
positions of the microlens array 120 and the pixel array 110, and
the like may be appropriately designed so that the projection size
of the light 123 on the pupil is sufficiently smaller than the
pupil diameter (in more detail, about 0.6 (mm) or less) in
consideration of a distance (that is, DLP) at which the user is
assumed to generally observe the display surface 125.
[0113] Also, in the display device 10, the arrangement of each
constituent member is set so that the irradiation state of light
with respect to each sampling region 207 is periodically iterated
in units larger than the maximum pupil diameter of the user. This
is for displaying a picture similar to that before a movement to a
user even at a position after a movement of the user's pupil
position when the position of the pupil of the user has moved. The
iteration cycle is determined by the pitch of the microlenses 121
of the microlens array 120, DXL, and DLP. Specifically, iteration
cycle=(pitch of microlens 121).times.(DLP+DXL)/DXL. On the basis of
this relationship, the pitch of the microlenses 121, the size dp
and the pitch of the pixels 111 in the pixel array 110, and values
such as DXL and DLP are set so that the iteration cycle satisfies
the above-described conditions. The conditions required for the
iteration cycle will be described in detail again in the following
(2-2-3-2. Iteration cycle of irradiation state of sampling
region).
[0114] As described above, the configuration of the display device
10 according to the first embodiment has been described with
reference to FIG. 10.
[0115] Here, the display device 10 according to the first
embodiment is similar to a light-ray reproduction type display
device widely used as a naked-eye 3D display device in terms of a
partial configuration. However, because an objective of the
naked-eye 3D display device is to display a picture having
binocular parallax with respect to the left and right eyes of the
user, the emission state of emitted light is controlled only in the
horizontal direction and the control of the emission state is not
performed in the vertical direction in many cases. Accordingly, for
example, in many cases, a configuration in which a lenticular lens
is provided on the display surface of the pixel array is provided.
On the other hand, because an objective of the display device 10
according to the first embodiment is to display a virtual image for
the purpose of compensating for the eye adjustment function for the
user, the control of the emission state is naturally performed in
both directions of the horizontal direction and the vertical
direction. Thus, instead of the lenticular lens as described above,
the microlens array 120 in which the microlenses 121 are
two-dimensionally arranged is used on the display surface of the
pixel array.
[0116] Also, because an objective of the naked-eye 3D display
device is to display a picture having binocular parallax with
respect to the left and right eyes of the user as described above,
the sampling region 207 described in the first embodiment is set as
a relatively large region including the whole eye of the user.
Specifically, the size of the sampling region 207 is set to about
65 (mm), which is the average value of a user's pupil distance
(PD), or about a fraction thereof in many cases. On the other hand,
in the first embodiment, the size of the sampling region 207 is set
to be smaller than the pupil diameter of the user, in more detail,
smaller than about 0.6 (mm). As described above, because the
purpose and the field of application are different, a structure
different from that of a general naked eye 3D display device is
adopted and different drive control is performed in the display
device 10 according to the first embodiment.
(2-2-2. Driving Example)
[0117] Next, a specific driving example in the display device 10
illustrated in FIG. 10 will be described. The display device 10
according to the first embodiment can be driven in a mode in which
a virtual image on a virtual display surface different from the
real display surface 125 is displayed (that is, picture information
to which depth information is assigned is displayed) (hereinafter
also referred to as a visual acuity compensation mode) or a mode in
which two-dimensional picture information is displayed (hereinafter
also referred to as a normal mode). Because the virtual image is
visually recognized by a user in the visual acuity compensation
mode, it is possible to provide a favorable picture even for a user
for which it is difficult to align a focus on the real display
surface 125 due to presbyopia or myopia. On the other hand, in the
normal mode, it is possible to display, for example, a
two-dimensional picture similar to that of the general
two-dimensional display device 80 illustrated in FIG. 6, with the
configuration of the display device 10 illustrated in FIG. 10.
(2-2-2-1. Normal Mode)
[0118] Driving of the display device 10 in the normal mode will be
described with reference to FIGS. 11 to 13. FIG. 11 is a diagram
illustrating light rays emitted from the microlens 121 in the
normal mode. FIG. 12 is a diagram illustrating a specific display
example of the pixel array 110 in the normal mode. FIG. 13 is a
diagram illustrating a positional relationship between the virtual
image surface 150 and the display surface 125 of the microlens
array 120 in the normal mode.
[0119] Referring to FIG. 11, as in FIG. 9, the microlens array 120
and the display surface 125 thereof, the user's eye lens 201, and
the user's retina 203 are schematically illustrated. Also, the
picture 160 displayed on the display surface 125 is schematically
illustrated. Also, FIG. 11 corresponds to an example in which the
picture 160 reproduced by the pixel array 810 in FIG. 8 described
above is reproduced by a configuration similar to that in the first
embodiment illustrated in FIG. 9. Accordingly, repeated description
of matters already described with reference to FIG. 8 and FIG. 9
will be omitted.
[0120] As illustrated in FIG. 11, in the normal mode, the same
light is emitted from each microlens 121 in directions of all
emission angles. Thereby, each microlens 121 behaves as in each
pixel 811 of the pixel array 810 illustrated in FIG. 8 and the
picture 160 is displayed on the display surface 125 of the
microlens array 120 by the microlens array 120.
[0121] FIG. 12 illustrates an example of a picture 160 that the
user can actually visually recognize in the normal mode and a state
in which a partial region of the pixel array 110 when the picture
160 is being displayed is enlarged. For example, as illustrated in
FIG. 12, in the normal mode, the user is assumed to visually
recognize the picture 160 including predetermined text data.
[0122] Here, the picture 160 in FIG. 12 is actually recognized by
the user when the user sees the light from the pixel array 110 via
the microlens array 120. An illustration obtained by enlarging a
partial region 161 of the picture 160 and removing the microlens
array 120 (that is, an illustration of the display of the pixel
array 110 immediately below the region 161) is illustrated on the
right side in FIG. 12. A pixel group 112 including a plurality of
pixels 111 is located immediately below one microlens 121, but the
same information is displayed in a pixel group 112 located
immediately below one microlens 121 in the normal mode as
illustrated on the right side of FIG. 12.
[0123] In this manner, each pixel 111 is driven so that the same
information is displayed in the pixel group 112 immediately below
each microlens 121 in the normal mode, so that two-dimensional
picture information is displayed on the display surface 125 of the
microlens array 120. The user can visually recognize a
two-dimensional picture existing on the display surface 125 similar
to the picture 160 provided in the general two-dimensional display
device as illustrated in FIG. 8.
[0124] FIG. 13 illustrates relationships between the user's eye
211, the display surface 125 of the microlens array 120, and the
virtual image surface 150. The normal mode corresponds to a state
in which the virtual image surface 150 and the display surface 125
of the microlens array 120 coincide as illustrated in FIG. 13.
(2-2-2-2. Visual Acuity Compensation Mode)
[0125] Next, the driving of the display device 10 in the visual
acuity compensation mode will be described with reference to FIGS.
14 to 16. FIG. 14 is a diagram illustrating light rays emitted from
the microlens 121 in the visual acuity compensation mode. FIG. 15
is a diagram illustrating a specific display example of the pixel
array 110 in the visual acuity compensation mode. FIG. 16 is a
diagram illustrating a positional relationship between the virtual
image surface 150 and the display surface 125 of the microlens
array 120 in the visual acuity compensation mode.
[0126] Referring to FIG. 14, as in FIG. 9, the microlens array 120
and the display surface 125 thereof, the virtual image surface 150,
the virtual pixels 151 on the virtual image surface 150, the
picture 160 on the virtual image surface, the lens 201 of the eye
of the user, and the user's retina 203 are schematically
illustrated. Also, in FIG. 14, the display surface 115 of the pixel
array 110, which is not illustrated in FIG. 9, is also
illustrated.
[0127] Also, FIG. 14 corresponds to an illustration obtained by
adding the display surface 115 of the pixel array 110 to FIG. 9
described above. Accordingly, repeated description of matters
already described with reference to FIG. 9 will be omitted.
[0128] In the visual acuity compensation mode, light is emitted
from each microlens 121 to reproduce the light from the picture 160
on the virtual image surface 150. The picture 160 can be considered
as a two-dimensional picture on the virtual image surface 150
displayed by the virtual pixels 151 on the virtual image surface
150. A range 124 of light that can be independently controlled in
one certain microlens 121 is schematically illustrated in FIG. 14.
The pixel group 112 (a part of the pixel array 110) immediately
below the microlens 121 is driven such that the light from the
virtual pixels 151 is reproduced on the virtual image surface 150
included in the range 124. Similar drive control is performed in
each microlens 121, so that light is emitted from each microlens
121 to reproduce the light from the picture 160 on the virtual
image surface 150.
[0129] An example of a picture 160 capable of being actually
visually recognized by the user in the visual acuity compensation
mode and a state in which a partial region of the pixel array 110
when the picture 160 is being displayed is enlarged are illustrated
in FIG. 15. For example, as illustrated in FIG. 15, the user is
assumed to visually recognize the picture 160 including
predetermined text data. In the visual acuity compensation mode,
the picture 160 is visually recognized by the user as a picture
displayed on the virtual image surface 150 illustrated in FIG.
14.
[0130] Here, the picture 160 in FIG. 15 is actually recognized by
the user when the user views the light from the pixel array 110 via
the microlens array 120. An illustration obtained by enlarging a
partial region 161 of the picture 160 and removing the microlens
array 120 (that is, an illustration of the display of the pixel
array 110 immediately below the region 161) is illustrated on the
right side in FIG. 15.
[0131] A pixel group 112 including a plurality of pixels 111 is
located immediately below one microlens 121. As illustrated in the
drawing on the right side of FIG. 15, in the pixel group 112
located immediately below each microlens 121, the same information
as in the normal mode is displayed in pixels located on an
extension of the center of the microlens 121 when viewed from a
certain point (that is, the same information is displayed on the
pixel 111a illustrated in FIG. 12 and the pixel 111b illustrated in
FIG. 15), but picture information that can be viewed through the
movement of the viewpoint of the user is displayed around the
pixels 111a and 111b.
[0132] Relationships between the user's eye 211, the display
surface 125 of the microlens array 120, and the virtual image
surface 150 are illustrated in FIG. 16. As illustrated in FIG. 16,
in the visual acuity compensation mode, the virtual image surface
150 is located farther away than the display surface 125 by the
microlens array 120. In FIG. 16, the movement of the viewpoint of
the user is indicated by an arrow. In consideration of movement of
the point visually recognized by the user on the virtual image
surface 150 (movement from a point S to a point T in FIG. 16)
corresponding to the movement of the user's viewpoint, picture
information that can be viewed through the movement of the
viewpoint is displayed on the pixel group 112 immediately below the
microlens 121 as illustrated in FIG. 15. Each pixel 111 is driven
as described above, so that the picture 160 is displayed to the
user as if it were located on the virtual image surface 150.
[0133] Examples of driving in the normal mode and the visual acuity
compensation mode have been described above as an example of
driving in the display device 10.
(2-2-3. Detailed Design)
[0134] A more detailed design method for each configuration in the
display device 10 illustrated in FIG. 10 will be described. Here,
conditions required for the size of the sampling region 207
illustrated in FIG. 10 and conditions required for the iteration
cycle of the irradiation state of light for each sampling region
207 will be described.
(2-2-3-1. Sampling Region)
[0135] As described above, it is preferable that the size of the
sampling region 207 be sufficiently small with respect to the pupil
diameter of the user so that a favorable image without blur is
provided to the user. Hereinafter, the conditions required for the
size of the sampling region 207 will be specifically examined.
[0136] For example, a level at which presbyopia can be first
recognized is about 1 D (Diopter) as the strength of a necessary
correction lens (presbyopic glasses). Here, if a Listing model
obtained by modeling an average eyeball is used, the eyeball can be
regarded to include a single lens of 60 D and a retina located at a
distance of 22.22 (mm) from the single lens.
[0137] Light is incident on the retina via a lens of 60 D-1 D=59 D
for the user wearing presbyopic glasses with an intensity of 1 D
described above, so that the image formation surface can be formed
at a position of 22.22.times.(60 D/59 D-1).apprxeq.0.38 (mm) behind
the retina in the eyeball of the user. Also, in this case, when the
entrance pupil diameter of light (corresponding to the projection
size of the light 123 on the pupil illustrated in FIG. 10) is Ip,
an amount of blur on the retina being Ip.times.0.38/22.22 (mm) can
be obtained.
[0138] Here, when the visual acuity required for practical use is
0.5, the size of the image on the retina to be distinguished is
about 0.0097 (mm) from the calculation shown in the following
Equation (1). In the following Equation (1), 1.33 is a refractive
index in the eyeball.
[Math. 1]
(1/(0.5.times.60)).times.(.pi./180).times.22.22/1.33.apprxeq.0.0097
(mm) (1)
[0139] If the amount of blur on the retina is smaller than the size
of the image on the retina to be distinguished, the user can
observe a clear image without blur. If Ip is obtained so that the
above-described amount of blur on the retina (Ip.times.0.38/22.22
(mm)) is the size (0.0097 (mm)) of the image on the retina to be
distinguished, Ip is about 0.6 (mm) from the following Equation
(2).
[Math. 2]
Ip=0.0097.times.22.22/0.384.apprxeq.0.6 (mm) (2)
[0140] When the degree of presbyopia is stronger, the distance of
0.38 (mm) between the retina and the image formation surface
described above becomes longer, so that Ip becomes smaller from the
above-described Equation (2). Also, when the required visual acuity
is larger, a larger value is substituted for "0.5" in the
above-described Equation (1), so that the size of the image on the
retina to be distinguished is smaller than the above-described
value (0.0097 (mm)) and Ip becomes smaller from the above-described
Equation (2). Accordingly, it can be said that Ip.apprxeq.0.6 (mm)
calculated from the above-described Equation (2) substantially
corresponds to a lower limit value required for an entrance pupil
diameter of light.
[0141] In the first embodiment, because the light incident on each
sampling region 207 is controlled, the size of the sampling region
207 is determined depending on the entrance pupil diameter of
light. Accordingly, it can also be said that Ip.apprxeq.0.6 (mm)
calculated from the above-described Equation (2) is the lower limit
value of the sampling region 207. As described above, in the first
embodiment, the sampling region 207 is preferably set so that its
size is 0.6 (mm) or less.
[0142] FIG. 17 is a diagram illustrating a relationship between the
pupil diameter of the user's pupil and the size of the sampling
region 207. In FIG. 17, the sampling region 207 set on the pupil of
the user together with the user's eye 211 is schematically
illustrated. A general human pupil diameter D is known to be about
2 (mm) to 8 (mm). On the other hand, as described above, a size ds
of the sampling region 207 is preferably 0.6 (mm) or less.
Accordingly, in the first embodiment, as illustrated in FIG. 17, a
plurality of regions 207 are set in the pupil. Although a case in
which the shape of the sampling region 207 is square has been
described here, the shape of the sampling region 207 may be any of
other various shapes such as a hexagon and a rectangle if the
above-described conditions of the size are satisfied.
[0143] The conditions required for the size of the sampling region
207 have been described above.
[0144] Here, in the above-described Patent Literature 1, a
configuration in which light from a plurality of pixels is emitted
from each of a plurality of microlenses and projected onto the
pupil of the user is also disclosed. However, in the technology
described in Patent Literature 1, only one of projected images of
light corresponding to pixels is incident on the user's pupil. This
corresponds to the state in which only one sampling region 207
smaller than the pupil diameter is provided on the pupil at an
interval equal to or larger than the pupil diameter in the first
embodiment.
[0145] In the technology described in the above-described Patent
Literature 1, blur is decreased by decreasing a size of a light
beam incident on the pupil without performing a process of
obtaining the light beam being incident on different points on the
pupil through the virtual image generation process as in the first
embodiment. Accordingly, when a plurality of light beams are
incident on the pupil from the same lens, blur occurs in the image
on the retina. Accordingly, in the technology described in the
above-described Patent Literature 1, the interval of the light
incident on the plane 205 including the pupil, that is, the
interval at which the sampling regions 207 are provided is adjusted
to be larger than the pupil diameter.
[0146] However, in this configuration, there is inevitably a moment
when light is not incident on the pupil when the pupil of the user
moves (that is, when the viewpoint moves), and the user
periodically observes an invisible region such as a black frame.
Accordingly, it is difficult to say that sufficiently favorable
display for the user is provided in the technology described in the
above-described Patent Literature 1.
[0147] On the other hand, in the first embodiment, as described
above, the size ds of the sampling region 207 is preferably 0.6
(mm) or less and a plurality of sampling regions 207 are set on the
pupil as illustrated in FIG. 17. Then, light incident on each
sampling region 207 is controlled. Accordingly, even when the
viewpoint moves, there is no phenomenon in which pictures are
discontinuously displayed as in the technology described in the
above-described Patent Literature 1 and it is possible to provide
the user with more preferable display.
(2-2-3-2. Iteration Cycle of Irradiation State of Sampling
Region)
[0148] As described above, in the first embodiment, in order to
cope with the movement of the user's viewpoint, a distance (DLP)
between the lens surface 125 of the microlens array 120 and the
pupil, a distance (DXL) between the pixel array 110 and the
microlens array 120, a pitch of the microlenses 121 in the
microlens array 120, a pixel size and a pitch of the pixel array
110, and the like are set so that the irradiation state of light on
each sampling region 207 is periodically iterated in units larger
than the maximum pupil diameter of the user. The conditions
required for the iteration cycle of the irradiation state of the
sampling region 207 will be specifically examined.
[0149] The iteration cycle of the irradiation state of the sampling
region 207 (hereinafter also simply referred to as an iteration
cycle) can be set on the basis of the user's pupil distance (PD).
Assuming that a group of sampling regions 207 corresponding to one
cycle of iteration cycles is called a sampling region group for
convenience, an iteration cycle .lamda. corresponds to a size
(length) of the sampling region group.
[0150] Normal viewing is hindered at the moment when the viewpoint
of the user transits between sampling region groups. Accordingly,
in order to decrease a frequency of occurrence of disturbance of
such display in accordance with the movement of the viewpoint of
the user, the optimum design of the iteration cycle .lamda. is
important.
[0151] For example, if the iteration cycle .lamda. is larger than
the PD, the left and right eyes can be included within the same
iteration cycle. Accordingly, for example, the naked eye 3D display
technology is used, so that it is possible to perform stereoscopic
viewing as well as display for compensating for the visual acuity
described in the above (2-2-2-2. Visual acuity compensation mode).
Also, although normal viewing is hindered at the moment when the
viewpoint of the user transits between the sampling region groups,
the frequency of disturbance of such display can be decreased
because the frequency of transition of the user's viewpoint between
sampling region groups is lowered even when the viewpoint is moved
by increasing the iteration cycle .lamda.. In this manner, when
implementing functions other than visual acuity compensation such
as stereoscopic vision, it is preferable that the iteration cycle
.lamda. be as large as possible.
[0152] However, in order to increase the iteration cycle .lamda.,
it is necessary to increase the number of pixels 111 of the pixel
array 110. An increase in the number of pixels causes manufacturing
costs and power consumption to be increased. Accordingly, there is
inevitably a limit to increasing the iteration cycle .lamda..
[0153] From the viewpoints of manufacturing costs and power
consumption, when the iteration cycle .lamda. is set to be equal to
or less than PD, it is desirable that the iteration cycle .lamda.
be set to satisfy the following Equation (3). Here, n is an
arbitrary natural number.
[Math. 3]
.lamda..times.n=PD (3)
[0154] A relationship between .lamda. and PD when the iteration
cycle .lamda. satisfies the above-described Equation (3) is
illustrated in FIG. 18. FIG. 18 is a diagram illustrating the
relationship between .lamda. and PD when the iteration cycle
.lamda. satisfies Equation (3). Positional relationships between
the sampling region group 213 including sampling regions 207 and
the left and right eyes 211 of the user when the iteration cycle
.lamda. satisfies the above-described Equation (3) are illustrated
in FIG. 18. In the example illustrated in FIG. 18, the sampling
region group 213 is set as a substantially square region in a plane
including the pupil of the user.
[0155] Here, as described above, normal viewing is hindered at the
moment when the viewpoint of the user transits between the sampling
region groups 213. However, when the iteration cycle .lamda.
satisfies the above-described Equation (3), for example, when the
user's viewpoint moves in the left and right directions of the
drawing sheet, the left and right eyes 211 pass through the
boundary between the sampling region groups 213 at the same time.
Accordingly, if a continuous region in which normal viewing is
possible in both of the left and right eyes 211 is referred to as a
continuous display region when the viewpoint moves, the continuous
display region can be maximized when the iteration cycle .lamda.
satisfies the above-described Equation (3). In FIG. 18, a width Dc
(continuous display width Dc) of the continuous display region in
the left-right direction on the drawing sheet is indicated by a
double-ended arrow. At this time, Dc=.lamda..
[0156] In contrast, when the iteration cycle .lamda. is set to
satisfy the following Equation (4), the continuous display region
becomes the smallest.
[Math. 4]
.lamda..times.(n+0.5)=PD (4)
[0157] A relationship between .lamda. and PD when the iteration
cycle .lamda. satisfies the above-described Equation (4) is
illustrated in FIG. 19. FIG. 19 is a diagram illustrating the
relationship between .lamda. and PD when the iteration cycle
.lamda. satisfies Equation (4). Positional relationships between
the sampling region group 213 including the sampling regions 207
and the left and right eyes 211 of the user when the iteration
cycle .lamda. satisfies Equation (4) are illustrated in FIG.
19.
[0158] In FIG. 19, as in FIG. 18, the width Dc (continuous display
width Dc) in the left-right direction of the drawing sheet of the
continuous display region is indicated by a double-end arrow. As
illustrated in FIG. 19, when the iteration cycle .lamda. satisfies
the above-described Equation (4), if the left and right eyes 211 of
the user only slightly move in the left-right direction of the
drawing sheet, either one of the left and right eyes 211 will pass
through the boundary between sampling region groups 213. Therefore,
when the iteration cycle .lamda. satisfies the above-described
Equation (4), the continuous display region becomes smaller. At
this time, Dc=.lamda./2.
[0159] FIG. 20 is a diagram illustrating an influence of the
relationship between the iteration cycle .lamda. and the PD on the
size of the continuous display region. In FIG. 20, a ratio between
the iteration cycle .lamda. and the PD (iteration cycle .lamda./PD)
is taken on the horizontal axis, a ratio between the continuous
display width Dc and PD (continuous display width Dc/PD) is taken
on the vertical axis, and a relationship between the two ratios is
plotted.
[0160] As illustrated in FIG. 20, when the iteration cycle .lamda.
satisfies the above-described Equation (3) (corresponding to the
point where the value on the horizontal axis is 1, 1/2, 1/3, . . .
), the continuous display width Dc/PD has the same value as the
iteration cycle .lamda./PD. That is, the continuous display width
Dc takes .lamda. which is a highest efficiency value.
[0161] On the other hand, when the iteration cycle .lamda.
satisfies the above-described Equation (4) (corresponding to the
point where the value on the horizontal axis is 1/1.5, 1/2.5,
1/3.5, . . . ), the continuous display width Dc/PD takes a value of
1/2 of the iteration cycle .lamda./PD. That is, the continuous
display width Dc takes .lamda./2 which is a lowest efficiency
value.
[0162] The conditions required for the iteration cycle of the
irradiation state of the sampling region 207 have been described
above. As described above, it is also possible to apply the display
device 10 to another field of application such as stereoscopic
viewing by setting the iteration cycle .lamda. of the irradiation
state of the sampling region 207 to be larger than the PD. However,
because it is necessary to increase the number of pixels 111 of the
pixel array 110 in order to increase the iteration cycle .lamda.,
there is a limit in terms of manufacturing costs and power
consumption. On the other hand, when an objective is to only
compensate for the visual acuity, it is not always necessary to
make the iteration cycle .lamda. larger than PD. In this case, it
is desirable that the iteration cycle .lamda. be set to satisfy the
above-described Equation (3). By setting the iteration cycle
.lamda. to satisfy the above-described Equation (3), the continuous
display region can be maximized most efficiently and convenience
for the user can be further improved.
2-3. Display Control Method
[0163] The display control method executed in the display device 10
according to the first embodiment will be described with reference
to FIG. 21. FIG. 21 is a flowchart illustrating an example of a
processing procedure of the display control method according to the
first embodiment. Each process illustrated in FIG. 21 corresponds
to that executed by the control unit 130 illustrated in FIG.
10.
[0164] Referring to FIG. 21, in the display control method
according to the first embodiment, light-ray information is first
generated on the basis of region information, virtual image
position information, and picture information (step S101). The
region information is information about a sampling region group
including a plurality of sampling regions set on a plane including
the user's pupil and substantially parallel to the display surface
(the lens surface 125 of the microlens array 120) of the display
device 10 illustrated in FIG. 10. Also, the virtual image position
information is information about a position (virtual image
generation position) at which a virtual image is generated in the
display device 10 illustrated in FIG. 10. For example, the virtual
image generation position is set to a position in focus for the
user. Also, the picture information is two-dimensional picture
information to be presented to the user.
[0165] In the process shown in step S101, information indicating
the light-ray state is generated as light-ray information so that
light from the picture based on the picture information displayed
at the virtual image generation position based on the virtual image
position information is incident on each sampling region included
in the sampling region group. The light-ray information includes
information about the emission state of light in each microlens 121
and information about the irradiation state of the light to each
sampling region 207 for reproducing the light-ray state. Also, the
process shown in step S101 corresponds to, for example, a process
to be performed by the light-ray information generating unit 131
illustrated in FIG. 10.
[0166] Next, on the basis of the light-ray information, each pixel
is driven so that the incident state of light is controlled for
each sampling region (step S103). Thereby, the light-ray state as
described above is reproduced, and a virtual image of a picture
based on the picture information is displayed at the virtual image
generation position based on the virtual image position
information. That is, clear display in focus for the user is
implemented.
[0167] The display control method according to the first embodiment
has been described above.
2-4. Application Examples
[0168] Several application examples of the display device 10
according to the above-described first embodiment will be
described.
(2-4-1. Application to Wearable Device)
[0169] An example of a configuration in which the display device 10
according to the first embodiment is applied to a wearable device
will be described with reference to FIG. 22. FIG. 22 is a diagram
illustrating an example of a configuration in which the display
device 10 according to the first embodiment is applied to a
wearable device.
[0170] As illustrated in FIG. 22, the display device 10 according
to the first embodiment can be preferably applied to a device
having a relatively small display screen such as a wearable device
30. In the illustrated example, the wearable device 30 is a
wristwatch type device.
[0171] In a mobile device such as the wearable device 30, the size
of the display screen is limited to a relatively small size in
consideration of portability for the user. However, as described in
the above (1. Background of present disclosure), in recent years,
the amount of information handled by users has increased and it is
necessary to display more information on one screen. For example,
there is a possibility that it will be difficult for a user with
presbyopia to visually recognize the display on the screen due to
simply increasing the amount of information displayed on the
screen.
[0172] On the other hand, according to the first embodiment, as
illustrated in FIG. 22, a virtual image 155 of a picture displayed
on the display surface 125 can be generated at a position different
from the real display surface 125. Accordingly, the user can
observe fine display without wearing optical compensation
instruments such as presbyopic glasses. Accordingly, even for a
relatively small screen such as the wearable device 30, it is
possible to perform high-density display and provide more
information to the user.
(2-4-2. Application to Other Mobile Device)
[0173] An example of a configuration in which the display device 10
according to the first embodiment is applied to another mobile
device such as a smartphone will be described with reference to
FIG. 23. FIG. 23 is a diagram illustrating an example of a
configuration in which the display device 10 according to the first
embodiment is applied to another mobile device.
[0174] In the example of the configuration illustrated in FIG. 23,
when the display device 10 is mounted in a mobile device such as a
smartphone, a first housing 171 on which the pixel array 110 is
mounted and a second housing 172 on which the microlens array 120
is mounted are configured as different housings from each other and
the first housing 171 and the second housing 172 are connected to
each other by a connection member 173, so that the mobile device
having the display device 10 is configured. The first housing 171
corresponds to the main body of the mobile device and a processing
circuit for controlling the operation of the entire mobile device
including the display device 10 and the like may be mounted within
the first housing 171.
[0175] The connection member 173 is a bar-like member having rotary
shaft portions provided at both ends thereof. As illustrated, one
of the rotating shaft portions is connected to the side surface of
the first housing 171 and the other of the rotating shaft portions
is connected to the side surface of the second housing 172. In this
manner, the first housing 171 and the second housing 172 are
rotatably connected to each other by the connection member 173.
Thereby, as illustrated, switching between a state in which the
second housing 172 is in contact with the first housing 171 ((a) in
FIG. 23) and a state in which the second housing 172 is located at
a predetermined distance from the first housing 171 ((b) in FIG.
23) is performed.
[0176] Here, as described in the above (2-2-1. Device
configuration), in the display device 10, the lens inter-pixel
distance DXL is an important factor for determining the projection
size of the light beam on the pupil, the iteration cycle of the
irradiation state of light with respect to each sampling region
207, and the like. However, if the mobile device is configured so
that the predetermined DXL is always secured when the display
device 10 is mounted on the mobile device, the volume of the mobile
device is increased and the increase in the volume is not
preferable from the viewpoint of portability. Accordingly, when
mounting the display device 10 on the mobile device, it is
preferable that a movable mechanism that makes the DXL variable be
provided in the microlens array 120 and the pixel array 110.
[0177] The configuration illustrated in FIG. 23 shows an example of
a configuration in which such a movable mechanism is provided in
the display device 10. In the mobile device illustrated in FIG. 23,
when the display device 10 is not used, the mobile device is set to
a state in which the second housing 172 is in contact with the
first housing 171 as illustrated in (a) of FIG. 23. In this state,
the microlens array 120 and the pixel array 110 are arranged so
that the DXL becomes smaller and the mobile device can be kept at a
smaller volume. On the other hand, in the mobile device illustrated
in FIG. 23, the length of the connection member 173 is adjusted so
that the DXL becomes a predetermined distance taking into
consideration the projection size of the light beam on the pupil
and/or the iteration cycle of the irradiation state of light in the
state in which the second housing 172 illustrated in (b) of FIG. 23
is located at a predetermined distance from the first housing 171.
Accordingly, by setting the second housing 172 to be separated from
the first housing 171 as illustrated in (b) of FIG. 23 when the
display device 10 is used, it is possible to arrange the microlens
array 120 and the pixel array 110 so that the DXL has a
predetermined distance taking into consideration various conditions
described above and perform display in the visual acuity
compensation mode.
[0178] In this manner, by providing a mechanism for making the DXL
variable when the display device 10 is mounted on a mobile device,
both of the decrease of the volume when it is not used (that is,
when it is carried) and the visual acuity compensation effect when
it is used can coexist and convenience for the user can be further
improved.
[0179] Also, even when the DXL is minimized when it is not used,
the display device 10 can perform display in the normal mode.
Because the lens effect in the microlens array 120 is also
minimized when the DXL is minimized, display can be performed in
the same manner as ordinarily (that is, there is no visual acuity
compensation effect) due to the pixel array 110. Also, in the
configuration example illustrated in FIG. 23, a movable mechanism
that makes the distance between the first housing 171 and the
second housing 172 variable is provided, but an example of a
configuration of the mobile device is not limited to this example.
For example, instead of or in addition to the movable mechanism, a
detachable mechanism capable of detaching the second housing 172
from the first housing 171 may be provided. With an
attaching/detaching mechanism, the mobile device can be kept at a
small volume when the display device 10 is not used by detaching
the second housing 172 from the first housing 171, and the second
housing 172 is attached at a predetermined distance from the first
housing 171 when the display device 10 is used and therefore
display in the visual acuity compensation mode can be
performed.
(2-4-3. Application to Electronic Loupe Device)
[0180] Generally, a visual acuity compensation device (hereinafter
referred to as an "electronic loupe device") in which a camera is
provided on the surface of a housing and information on the paper
surface photographed by the camera is enlarged and displayed on a
display screen provided on the back surface of the housing is
known. A user can read an enlarged map, characters, or the like via
the display screen by placing the electronic loupe device on, for
example, a surface of paper such as a map or a newspaper, so that
the camera faces the paper surface. The display device 10 according
to the first embodiment can also be preferably applied to such an
electronic loupe device.
[0181] FIG. 24 illustrates an example of a general electronic loupe
device. FIG. 24 is a diagram illustrating an example of a general
electronic loupe device. As described above, the camera is mounted
on the surface of the housing of the electronic loupe device 820.
As illustrated, the electronic loupe device 820 is placed on a
paper surface 817 so that the camera faces the paper surface 817.
Graphics, characters, and the like on the paper surface 817
photographed by the camera are appropriately enlarged and displayed
on the display screen of the back side of the housing of the
electronic loupe device 820. Thereby, for example, a user who
experiences difficulty in reading graphics and characters with
small sizes due to presbyopia or the like can read the information
on the paper surface more easily.
[0182] Here, the general electronic loupe device 820 as illustrated
in FIG. 24 merely enlarges and displays a captured picture simply
at a predetermined magnification, unlike a loupe made of optical
lenses. Accordingly, because the user needs to enlarge the display
to such an extent that it can be read without blur, the number of
characters (an amount of information) to be displayed on the
display screen at a time decreases. Consequently, when attempting
to read a wide area of information within the paper surface 817, it
is necessary to frequently move the electronic loupe device 820 on
the paper surface 817.
[0183] On the other hand, when the display device 10 according to
the first embodiment is mounted on the electronic loupe device, for
example, a configuration example in which a camera is mounted on
the front surface of the housing and the display device 10 is
mounted on the back surface of the housing can be conceived. By
placing the electronic loupe device so that the surface on which
the camera is provided faces the paper surface and driving the
electronic loupe device, a picture including information on the
paper surface photographed by the camera can be displayed by the
display device 10 mounted on the back surface of the housing.
[0184] If the display device 10 is driven in the visual acuity
compensation mode, it is possible to perform display for remedying
blur originally due to presbyopia or the like without enlarging the
picture. As described above, in an electronic loupe device on which
the display device 10 is mounted, unlike a general electronic loupe
device 820, it is possible to perform visual acuity compensation
without decreasing the amount of information to be displayed on the
display screen at a time. Accordingly, even when a wide area of
information within the paper surface is intended to be read, it is
not necessary to frequently move the electronic loupe device on the
paper surface and the user's readability can be significantly
improved.
[0185] Several application examples of the display device 10
according to the first embodiment have been described above.
However, the first embodiment is not limited to the above-described
examples and the device to which the display device 10 is applied
may be another device. For example, the display device 10 may be
mounted on a mobile device in a form other than a wearable device
or a smartphone. Alternatively, a device to which the display
device 10 is applied is not limited to a mobile device and may be
applied to any device as long as a device having a display function
such as a stationary television is provided.
(2-4-4. Application to in-Vehicle Display Device)
[0186] In recent years, in automobiles, technology for displaying
driving support information on a display device and presenting the
driving support information to a driver has been developed. For
example, there is technology for providing a display device on an
instrument panel of a dashboard and displaying information about
instruments such as a speedometer and a tachometer on the display
device. Technology for providing a display device instead of a
mirror at a position corresponding to a rearview mirror or a door
mirror and displaying a video captured by the in-vehicle camera on
the display device to replace the mirror is also known.
[0187] Here, the driver is considered to repeatedly view the
outside world through the windshield and view instruments and
mirrors present relatively close to the driver when focusing on the
movement of the visual line of the driver during driving. That is,
the visual line of the driver can reciprocate back and forth
between a far position and a near position. At this time, focusing
is performed in accordance with the movement of the visual line in
the eyes of the driver, but the time taken for the focusing is
problematic in terms of ensuring safety in a vehicle moving at a
high speed. Even when instruments and mirrors are replaced with
display devices as described above, a similar problem may
occur.
[0188] On the other hand, by applying the display device 10
according to the first embodiment to the in-vehicle display device
for displaying the driving support information as described above,
the above-described problem can be solved.
[0189] Specifically, because the virtual image can be generated
behind (at a position far from) the real display surface (that is,
the microlens array 120), the display device 10 can display various
kinds of information at a distance similar to that when the user
views the outside world via the windshield when the user as the
driver views the display device 10 by setting a virtual image
generation position to a sufficiently far position. Accordingly,
even when the user alternately views the state of the outside world
and the driving support information in the in-vehicle display
device 10, the time required for focusing can be shortened.
[0190] As described above, the display device 10 can be preferably
applied to an on-vehicle display device that displays driving
support information. By applying the display device 10 to the
in-vehicle display device, there is a possibility of fundamentally
solving the safety problem caused by the focusing time of the
driver's field of view as described above.
2-5. Modified Example
[0191] Several modified examples of the first embodiment described
above will be described.
(2-5-1. Decrease of Pixel Size in Accordance with Aperture)
[0192] As described in the above (2-2-1. Device configuration), in
the display device 10, there are correlations between a projection
size (corresponding to the sampling region 207) of light on the
pupil from a pixel, image magnification, and a size (resolution) of
a pixel 111 of the pixel array 110. Specifically, assuming that the
size of the sampling region 207 is ds, the size of the pixel 111 is
dp, and the image magnification is m, they have a relationship
shown in the following Equation (5).
[Math. 5]
ds=dp.times.m (5)
[0193] Also, the image magnification m is represented as a ratio
between a viewing distance (a distance between the lens surface 125
of the microlens array 120 and the pupil illustrated in FIG. 10)
DLP and a lens inter-pixel distance (a distance between the lens
surface 125 of the microlens array 120 and the display surface 115
of the pixel array 110 illustrated in FIG. 10) DXL by the following
Equation (6).
[Math. 6]
m=DLP/DXL (6)
[0194] Here, a focal length f of the microlens 121 is assumed to
satisfy the following Equation (7).
[Math. 7]
1/f=1/DLP+1/DXL (7)
[0195] As shown in the above-described Equations (5) and (6), the
size dp of the pixel 111 is determined by the image magnification
of the projection system of the microlens 121 that projects the
pixel 111 onto the user's pupil. For example, according to
requirements of another design matter, when the DXL needs to be
decreased in a product or when the DLP needs to be increased, the
image magnification m may need to be increased and the size dp of
the pixel 111 may need to be decreased.
[0196] Here, if the size dp of the pixel 111 is simply decreased,
the number of pixels 111 included in the pixel array 110 is
increased and the increase in the number of pixels 111 may be
undesirable in terms of manufacturing costs or power consumption.
Therefore, as a method of decreasing the size dp of the pixel 111
while keeping the size ds of the sampling region at a small value
and without increasing the number of pixels, a method of decreasing
the size dp of the pixel 111 using a shielding plate having an
aperture may be conceived. Also, in order to distinguish it from a
shielding plate provided with an aperture used in the following
(2-5-2. Example of configuration of light emission point other than
microlens), the shielding plate used to decrease the size dp of the
pixel 111 may be referred to as a first shielding plate in the
present description.
[0197] FIG. 25 is a schematic diagram illustrating a state of a
decrease of a pixel size dp by a first shielding plate having a
rectangular opening (aperture). Referring to FIG. 25, the shielding
plate 310 is provided with a rectangular opening 311 at a position
corresponding to each pixel 111 (111R, 111G, or 111B). A pixel 111R
in FIG. 25 indicates a pixel that emits red light, a pixel 111G
indicates a pixel that emits green light, and a pixel 111B
indicates a pixel that emits blue light.
[0198] The size of the opening 311 is smaller than the sizes of the
pixels 111R, 111G, and 111B. By providing the shielding plate 310
to cover the pixels 111R, 111G, and 111B, it is possible to
apparently decrease the sizes dp of the pixels 111R, 111G, and
111B.
[0199] FIG. 26 is a diagram illustrating an example of another
configuration of the first shielding plate and is a schematic
diagram illustrating a state of a decrease of a pixel size dp by a
first shielding plate having a circular opening (aperture).
Referring to FIG. 26, the shielding plate 320 is provided with a
circular opening 321 at a position corresponding to each pixel 111
(111R, 111G, or 111B). The size of the opening 321 is smaller than
the sizes of the pixels 111R, 111G, and 111B. By providing the
shielding plate 320 to cover the pixels 111R, 111G, and 111B, it is
possible to apparently decrease the sizes dp of the pixels 111R,
111G, and 111B.
[0200] Here, in the examples illustrated in FIGS. 25 and 26, the
shielding plates 310 and 320 are provided on the display surface of
the pixel array 110. However, in this modified example, the
position at which the first shielding plate is provided is not
limited to the display surface. For example, when the pixel array
110 is provided as a transmissive pixel array such as a pixel array
of a liquid crystal display device, the first shielding plate may
be provided between the backlight and the liquid crystal layer
(liquid crystal panel) in the liquid crystal display device.
[0201] An example of a configuration in which such a first
shielding plate is provided between the backlight and the liquid
crystal layer is illustrated in FIG. 27. FIG. 27 is a diagram
illustrating an example of a configuration in which the first
shielding plate is provided between the backlight and the liquid
crystal layer.
[0202] A cross-sectional view in a direction perpendicular to the
display surface of a liquid crystal display device to which the
first shielding plate is added is illustrated in FIG. 27. Referring
to FIG. 27, the liquid crystal display device 330 includes a
backlight 331, a diffusion plate 332, an aperture film 333, a
polarization plate 334, a thin film transistor (TFT) substrate 335,
a liquid crystal layer 336, a color filter substrate 337, and a
polarization plate 338 stacked in this order. Because the
configuration of the liquid crystal display device 330 is similar
to that of a general liquid crystal display device except that the
aperture film 333 is provided, a detailed description of the
configuration will be omitted.
[0203] In this modified example, the pixel array of the liquid
crystal display device 330 includes the pixel array 110 illustrated
in FIG. 10. In FIG. 27, the microlens array 120 is also illustrated
to correspond with FIG. 10.
[0204] The aperture film 333 corresponds to the above-described
first shielding plates 310 and 320. The aperture film 333 has a
configuration in which a plurality of optical openings (apertures
(not illustrated)) are provided in correspondence with the
positions of the pixels in the light shielding member and the light
from the backlight 331 passes through the opening portion and is
incident on the liquid crystal layer 336. Accordingly, because the
aperture film 333 shields light outside a position at which the
opening is provided, the pixel size is substantially decreased.
[0205] Here, a reflection layer that reflects light may be provided
on the surface on the backlight side of the aperture film 333. When
the reflection layer is provided, light from the backlight 331 that
is not transmitted through the opening from light from the
backlight 331 is reflected by the reflection layer toward the
backlight 331. Reflected and returned light is reflected inside the
backlight 331 again and emitted toward the aperture film 333 again.
If there is no optical absorption in the reflecting surface of the
aperture film 333 and the backlight 331, all the light is ideally
reflected and incident on the liquid crystal layer 336 and loss of
light is eliminated. Alternatively, a similar effect can be
obtained also when the aperture film 333 itself of a material
having high reflectance is formed instead of providing the
reflection layer. In this manner, by providing a reflection layer
on the surface of the aperture film 333 on the backlight side or by
forming the aperture film 333 itself of a material with high
reflectance, loss of light can be minimized even when the size of
the opening is small, because light is recycled between the
backlight 331 and the aperture film 333, so to speak.
[0206] Also, as another configuration, it is also possible to
implement a configuration in which a positional relationship
between the aperture film 333 and the liquid crystal layer 336 is
reversed in the configuration example described above. In this
case, it is possible to use a self-luminous type display device
which is not a transmissive type instead of the liquid crystal
layer 336.
[0207] A modified example in which the pixel size is decreased
using the first shielding plate has been described above.
(2-5-2. Example of Configuration of Light Emission Point Other than
Microlens)
[0208] In the above-described embodiment, the display device 10 is
configured by arranging the microlens array 120 on the display
surface of the pixel array 110. In the display device 10, each
microlens 121 may function as a light emission point. Here, the
first embodiment is not limited to such an example, and the light
emission point may be implemented by a configuration other than a
microlens.
[0209] For example, instead of the microlens array 120 illustrated
in FIG. 10, a shielding plate having a plurality of openings
(apertures) can be used. In this case, each opening of the
shielding plate functions as a light emission point. Also, to
distinguish it from the shielding plate used in the above (2-5-1.
Decrease of pixel size in accordance with aperture), a shielding
plate used for configuring a light emission point instead of the
microlens array 120 may be referred to as a second shielding plate
in the present description.
[0210] The second shielding plate may have a configuration
substantially similar to a parallax barrier used for a general 3D
display device. In this modified example, a shielding plate having
an opening at a position corresponding to the center of each
microlens 121 illustrated in FIG. 10 is arranged on the display
surface 115 of the pixel array 110 instead of the microlens array
120.
[0211] From optical considerations similar to the above-described
Equations (5) and (6), the projection size of light (which
corresponds to the sampling region) becomes ((pixel size of pixel
array 110)+(diameter of aperture)).times.(distance between
shielding plate and pupil)/(distance between pixel array 110 and
shielding plate) when light from the pixel 111 passes through the
opening of the shielding plate and is projected onto the pupil of
the user. Accordingly, in consideration of the size of the sampling
region of 0.6 (mm) or less, the opening of the shielding plate can
be designed to satisfy the above-described conditions.
[0212] Here, when a shielding plate is used instead of the
microlens array 120, light not passing through the opening is not
emitted toward the user, resulting in a loss. Accordingly, compared
with when the microlens array 120 is provided, the display observed
by the user may become dark. Accordingly, when a shielding plate is
used instead of the microlens array 120, it is preferable that each
pixel be driven in consideration of such loss of light.
[0213] Also, when the pixel array 110 is configured using a
transmissive display device such as a liquid crystal display
device, a configuration in which the positional relationship
between the second shielding plate and the transmissive pixel array
110 is reversed can also be similarly implemented. In this case,
for example, the second shielding plate is arranged between the
backlight and the liquid crystal layer. In this case, as in the
configuration described above with reference to FIG. 27, it is
possible to obtain the effect of decreasing light loss by providing
a reflection layer on the backlight side surface of the second
shielding plate or forming the second shielding plate itself with a
material having high reflectance.
[0214] A modified example in which the light emission point is
implemented by a configuration other than a microlens has been
described above.
(2-5-3. Dynamic Control of Irradiation State in Accordance with
Pupil Position Detection)
[0215] As described in the above (2-2-1. Device configuration), the
display device 10 according to the first embodiment sets a sampling
region group including a plurality of sampling regions on a plane
including the user's pupil and controls the irradiation state of
light for each sampling region. Also, as described in the above
(2-2-3-2. Iteration cycle of irradiation state of sampling region),
the irradiation state of light for each sampling region is iterated
in a predetermined cycle. Here, when the user's eyes pass through a
boundary between the sampling region groups corresponding to one
cycle of iteration, the user does not recognize normal display.
[0216] As one method of avoiding such abnormal display when the
viewpoint passes through the boundary between the sampling region
groups, it is conceivable to increase the iteration cycle .lamda.
of the irradiation state of the sampling region. However, as
described in the above (2-2-3-2: Iteration cycle of irradiation
state of sampling region), when the iteration cycle .lamda. is
increased, the number of pixels in the pixel array is increased,
the pixel pitch is decreased, power consumption is increased, and
the like, thereby causing problems in terms of product
specifications.
[0217] Therefore, as another method of avoiding abnormal display
when the viewpoint passes through the boundary between the sampling
region groups, a method of detecting a position of the user's pupil
and dynamically controlling the irradiation state of the sampling
region in accordance with the detected position may be
conceived.
[0218] A configuration of a display device for implementing such
dynamic control of the irradiation state in accordance with pupil
position detection will be described with reference to FIG. 28.
FIG. 28 is a diagram illustrating an example of a configuration of
a display device according to a modified example in which dynamic
control of the irradiation state in accordance with the pupil
position detection is performed.
[0219] Referring to FIG. 28, the display device 20 according to the
present modified example includes a pixel array 110 in which a
plurality of pixels 111 are two-dimensionally arranged, a microlens
array 120 provided on a display surface 115 of the pixel array 110,
and a control unit 230 that controls driving of each pixel 111 of
the pixel array 110. Each pixel 111 is driven by the control unit
230 on the basis of the light-ray information, so that, for
example, the light-ray state of light from a picture on a virtual
image surface located at a predetermined position is reproduced.
Here, because the configurations and functions of the pixel array
110 and the microlens array 120 are similar to the configurations
and functions of these members in the display device 10 illustrated
in FIG. 10, a detailed description thereof will be omitted
here.
[0220] The control unit 230 includes, for example, a processor such
as a CPU or a DSP, and operates in accordance with a predetermined
program, thereby controlling the driving of each pixel 111 of the
pixel array 110. The control unit 230 has a light-ray information
generating unit 131, a pixel driving unit 132, and a pupil position
detecting unit 231 as functions thereof. Because the functions of
the light-ray information generating unit 131 and the pixel driving
unit 132 are substantially similar to the functions of these
configurations in the display device 10 illustrated in FIG. 10,
description of matters repeated from the control unit 130 of the
display device 10 will be omitted and differences from the control
unit 130 will mainly be described here.
[0221] On the basis of the region information, the virtual image
position information and the picture information, the light-ray
information generating unit 131 generates information indicating
the light-ray state when light from a picture displayed on the
virtual image surface is incident on each sampling region 207 as
light-ray information. For example, the information about the cycle
(iteration cycle .lamda.) of iteratively reproducing the
irradiation state of light for each sampling region 207 may be
included in the region information. When the light-ray information
is generated, the light-ray information generating unit 131
generates information about the irradiation state of light for each
sampling region 207 in consideration of the iteration cycle
.lamda..
[0222] The pixel driving unit 132 drives each pixel 111 of the
pixel array 110 so that the incident state of light is controlled
for each sampling region 207 on the basis of the light-ray
information. Thereby, the above-described light-ray state is
reproduced and a virtual image is displayed to the user.
[0223] The pupil position detecting unit 231 detects the position
of the user's pupil. As a method in which the pupil position
detecting unit 231 detects the position of the pupil, for example,
any known method used in general visual line detection technology
may be applied. For example, an imaging device (not illustrated)
capable of photographing at least the face of the user may be
provided in the display device 20, and the pupil position detecting
unit 231 analyzes a captured picture acquired by the imaging device
using a well-known picture analysis method, thereby detecting the
position of the user's pupil. The pupil position detecting unit 231
provides information about the detected pupil position of the user
to the light-ray information generating unit 131.
[0224] In the present modified example, the light-ray information
generating unit 131 generates information about the irradiation
state of light for each sampling region 207 so that that the pupil
of the user is not positioned at a boundary between the sampling
region groups, which are units of iterations of the irradiation
state for each sampling region 207, on the basis of information
about the position of the pupil of the user. The light-ray
information generating unit 131 generates information about the
irradiation state of light for each sampling region 207, for
example, so that the user's pupil is always located at
substantially the center of a sampling region group.
[0225] Each pixel 111 is driven by the pixel driving unit 132 on
the basis of the above-described light-ray information, so that the
position of the sampling region group in the sampling region groups
209 may be changed at any time in accordance with the movement of
the position of the user's pupil in the present modified example so
that the pupil is not positioned at a boundary between the sampling
region groups. Accordingly, it is possible to prevent the viewpoint
of the user from passing through a boundary between sampling region
groups and it is possible to avoid the occurrence of abnormal
display when the user's viewpoint passes through a boundary.
Consequently, it is possible to decrease the stress of the user
using the display device 20. Also, according to the present
modified example, as in the case in which the iteration cycle
.lamda. is increased, the manufacturing costs and the power
consumption are not increased, so that more comfortable display and
optimization of costs, etc. can be compatible.
[0226] A modified example in which dynamic control of the
irradiation state is performed in accordance with pupil position
detection has been described above.
(2-5-4. Modified Example in which Pixel Array is Implemented by
Printing Material)
[0227] Although the pixel array 110 is implemented as a
configuration of a display device such as, for example, a liquid
crystal display device, in the display device 10 described in the
above (2-2-1. Device configuration), the first embodiment is not
limited to such an example. For example, the pixel array 110 may be
implemented by a printing material.
[0228] When the pixel array 110 is implemented by a printing
material in the display device 10 illustrated in FIG. 10, a
printing control unit can be provided instead of the pixel driving
unit 132 as a function of the control unit 130. The printing
control unit has a function of obtaining information to be
displayed on the printing material through calculation on the basis
of the light-ray information generated by the light-ray information
generating unit 131 and controlling the operation of a printing
unit including a printing device such as a printer so that
information similar to that when the information is displayed on
the pixel array 110 is printed on the printing material. The
printing unit may be incorporated in the display device 10 or may
be provided as a separate device different from the display device
10.
[0229] By arranging the printing material printed under the control
of the printing control unit at the position of the pixel array 110
illustrated in FIG. 10 instead of the pixel array 110 and by using
appropriate illumination as necessary, it is possible to display a
virtual image at a predetermined position to the user and perform
display for compensating for the visual acuity of the user as in
the display device 10.
3. Second Embodiment
[0230] As described in the above (2-2-1. Device configuration), the
display device 10 according to the first embodiment provides
display corresponding to a virtual image to a user by reproducing a
light-ray state from the virtual image when the virtual image is
located at a predetermined position on the basis of virtual image
position information. At this time, in the first embodiment, the
position at which the virtual image is generated (the virtual image
generation position) is appropriately set in accordance with the
visual acuity of the user. For example, by setting the virtual
image generation position at a focal position corresponding to the
visual acuity of the user, it is possible to display a picture so
as to compensate for the visual acuity of the user. However, as
described below, when visual acuity compensation is performed by
light-ray reproduction as in the first embodiment, there are
predetermined restrictions when the display device 10 is configured
and a degree of freedom of design is low. Here, as the second
embodiment, an embodiment in which the user's visual acuity is
compensated for by a different technique with a device
configuration substantially similar to that of the display device
10 illustrated in FIG. 10 will be described.
3-1. Background of Second Embodiment
[0231] Prior to describing the configuration of the display device
according to the second embodiment in detail, the background of the
second embodiment that the present inventors have reached will be
described to make the effects of the second embodiment clearer.
[0232] First, the results of examination of the display device 10
according to the first embodiment by the present inventors will be
described. To effectively perform the visual acuity compensation in
the display device 10 according to the first embodiment, the
constituent members thereof needs to satisfy predetermined
conditions. Specifically, in the display device 10, the specific
configurations and arrangement positions of a pixel array 110 and a
microlens array 120 can be determined in accordance with the
performance required for a size ds for a sampling region 207, a
resolution, an iteration cycle .lamda., etc.
[0233] For example, as described in the above (2-2-3-1. Sampling
region), it is preferable that the size ds of the sampling region
207 be set to be sufficiently small with respect to a pupil
diameter of the user, specifically, 0.6 (mm) or less, to provide
the user with a favorable image that is not blurred. Here, there is
a relationship expressed by the following Equation (8) between the
size ds of the sampling region 207, a size dp of a pixel 111 of the
pixel array 110, a viewing distance (a distance between a lens
surface 125 of the microlens array 120 and the pupil) DLP, and a
lens inter-pixel distance (a distance between the lens surface 125
of the microlens array 120 and a display surface 115 of the pixel
array 110) DXL as shown in the above-described Equations (5) and
(6).
[ Math . 8 ] ds = dp .times. DLP DXL ( 8 ) ##EQU00001##
[0234] Accordingly, the size dp of the pixel 111, the viewing
distance DLP, and the lens inter-pixel distance DXL can be
determined in accordance with the size ds of the sampling region
207 required for the display device 10 (hereinafter referred to as
condition 1). As described above, because it is preferable that the
size ds of the sampling region 207 be small, for example, the size
dp of the pixel 111, the viewing distance DLP, and the lens
inter-pixel distance DXL are determined so that the size ds of the
sampling region 207 is small.
[0235] Also, in the display device 10, each microlens 121 of the
microlens array 120 behaves as a pixel. Accordingly, the resolution
of the display device 10 is determined by the pitch of the
microlenses 121. In other words, the pitch of the microlenses 121
can be determined in accordance with the resolution required for
the display device 10 (hereinafter referred to as condition 2).
Because it is generally preferable that the resolution be large,
for example, the pitch of the microlenses 121 is required to be
small.
[0236] Further, in terms of the resolution, the relationship of
(resolution) .varies.(viewing distance DLP+virtual image depth
DIL).times.lens inter-pixel distance DXL/(size dp of pixel
111.times.virtual image depth DIL) is established. Here, the
virtual image depth DIL is a distance from the microlens array 120
to the virtual image generation position. Accordingly, the size dp
of the pixel 111 and the lens inter-pixel distance DXL can also be
determined in accordance with the resolution required for the
display device 10 and the virtual image depth DIL (hereinafter
referred to as condition 3).
[0237] As described in the above (2-2-1. Device configuration), the
iteration cycle .lamda. has a relationship of .lamda.=(pitch of
microlens 121).times.(DLP+DXL)/DXL. Accordingly, the pitch of the
microlenses 121, the viewing distance DLP, and the lens inter-pixel
distance DXL can be determined in accordance with the iteration
cycle .lamda. required for the display device 10 (hereinafter
referred to as condition 4). As described in the above (2-2-3-2.
Iteration cycle of irradiation state of sampling region), it is
preferable that the iteration cycle .lamda. be large to more stably
provide normal viewing to the user. Accordingly, for example, the
pitch of the microlenses 121, the viewing distance DLP, and the
lens inter-pixel distance DXL are determined so that the iteration
cycle .lamda. becomes large.
[0238] As described above, in the display device 10, various values
related to the configurations and the arrangement positions of the
pixel array 110 and the microlens array 120 such as the size dp of
the pixel 111, the virtual image depth DIL, the pitch of the
microlenses 121, the viewing distance DLP, and the lens inter-pixel
distance DXL can be appropriately determined to satisfy conditions
1 to 4 required for the display device 10.
[0239] Here, when conditions 1 to 4 are considered to be
simultaneously satisfied, the size dp of the pixel 111, the virtual
image depth DIL, the pitch of the microlenses 121, the viewing
distance DLP, the lens inter-pixel distance DXL, and the like
cannot be independently set. For example, from the viewpoint of
product performance, the resolution and iteration cycle .lamda.
required for the display device 10 are assumed to be determined. In
this case, the pitch of the microlenses 121 can be determined to
satisfy the resolution required for the display device 10 on the
basis of condition 2. If the pitch of the microlenses 121 is
determined, the lens inter-pixel distance DXL can be determined to
satisfy the iteration cycle .lamda. required for the display device
10 on the basis of condition 4.
[0240] For example, because the viewing distance DLP can be set as,
for example, a distance at which the user generally observes the
display device 10, the degree of freedom in designing the viewing
distance DLP is small. Accordingly, if the pitch of the microlenses
121 and the lens inter-pixel distance DXL are determined, the size
dp of the pixel 111 is determined to satisfy the size ds of the
sampling region 207 required for the display device 10 on the basis
of condition 1. Consequently, if the size ds of the sampling region
207 is intended to be decreased, the size dp of the pixel 111 also
becomes relatively small in accordance therewith. As an example,
when the resolution and the iteration cycle .lamda. usable for
practical use are secured and the size ds of the sampling region
207 is intended to be 0.6 (mm) or less, it is necessary to set the
size dp of the pixel 111 to at least about several tens (.mu.m) or
less.
[0241] As described in the above (2-2-3-2: Iteration cycle of
irradiation state of sampling region), if the size dp of the pixel
111 is further decreased and the number of pixels 111 is increased,
manufacturing costs and power consumption may be increased. Also,
as a pixel to be used for a display surface of a general mobile
device such as a smartphone, a pixel having a size larger than
several tens (.mu.m) is widely used. Accordingly, because it is
difficult to appropriate such a generally widely used pixel array
for the pixel array 110 of the display device 10, it is necessary
to separately manufacture a dedicated pixel array and hence the
manufacturing costs may be increased.
[0242] Therefore, the present inventors investigated whether it is
possible to implement technology for executing visual acuity
compensation while maintaining the size dp of the pixel 111 at a
predetermined size in a device configuration substantially similar
to that of the display device 10.
[0243] The present inventors focused on the effect of optical
resolution by the lens. In the above-described embodiment, by
appropriately driving each pixel 111 of the pixel array 110 and
controlling the light-ray state, a virtual image of the picture on
the display surface of the pixel array 110 is generated at an
arbitrary position. On the other hand, in general, a convex lens
has a function of generating a virtual image of the physical object
enlarged at a predetermined magnification at a predetermined
position in accordance with a distance between the convex lens and
the physical object and its focal length f. If the user observes
the virtual image optically generated by such a convex lens, visual
acuity compensation for, for example, a user having presbyopia, is
considered to be able to be implemented.
[0244] FIG. 29 is an explanatory diagram illustrating generation of
a virtual image in a general convex lens. As illustrated in FIG.
29, in general, the convex lens 821 has a function of generating a
virtual image in which the physical object is enlarged at a
predetermined magnification behind the convex lens 821 (on an
opposite side of the convex lens 821 when viewed from the user
observing the physical object through the convex lens 821) when the
physical object is located at a distance closer than the focal
distance f. If the pixel array 110 is arranged at the position of
the physical object, the user observes the virtual image of the
picture on the display surface of the enlarged pixel array 110
through the convex lens 821. That is, this corresponds to an
arrangement of a general magnifying glass (loupe) on the display
surface of the pixel array 110.
[0245] There is a possibility that the amount of information to be
displayed on one screen may be decreased by enlarging and
displaying the physical object, but it is possible to cope with the
decrease in the amount of information by decreasing display in the
pixel array 110 in advance in view of the magnification of the
convex lens 821. That is, it is only necessary to adjust the size
of the picture to be displayed on the pixel array 110 so that the
picture has an appropriate size when the picture is enlarged and
observed as a virtual image by the user. Thereby, it is possible to
cause the user to observe a resolved picture without decreasing the
amount of information provided to the user.
[0246] Here, a process of performing the resolution as described
above with one convex lens as in a general magnifying glass may be
considered. For example, for a device configuration which can be
normally assumed, when the size of the pixel array 110 is about a
diagonal line length of 100 (mm) and a virtual image is generated
at a depth of 400 (mm) from the lens, the distance between the
pixel array 110 and the convex lens is about 20 (mm). In this case,
the convex lens is required to have an angle of view of about 100
(mm) and a focal length of about 21 (mm), that is, the F value is
required to be about 0.21, but a convex lens having such optical
characteristics is not realistic. In other words, it is considered
that it is difficult to implement the above-described visual acuity
compensation by optical resolution using one convex lens.
[0247] Here, when attention is paid to one microlens 121 of the
microlens array 120 in the configuration of the display device 10
illustrated in FIG. 10, each microlens 121 can have a function as a
magnifying glass similar to the above-described convex lens 821.
That is, each microlens 121 allows a user observing a physical
object through the microlenses 121 to observe a virtual image in
which the physical object is enlarged.
[0248] Accordingly, in the configuration of the display device 10
illustrated in FIG. 10, the microlens array 120 is arranged so that
a virtual image of the display of the pixel array 110 can be
generated by each microlens 121 of the microlens array 120 (that
is, so that a distance from the pixel array 110 to the microlens
121 is less than the focal length of the microlens 121), thereby
providing an enlarged and resolved picture (that is, a virtual
image) to the user even when light-ray reproduction is not
performed. At this time, if the size of the picture to be displayed
on the pixel array 110 is adjusted in consideration of the
magnification of each microlens 121 as described above, the amount
of information to be provided to the user does not decrease.
[0249] In this manner, the display device 10 illustrated in FIG. 10
can be regarded as a display device in which a plurality of lenses
(that is, microlenses 121) are arranged on the display surface side
of the pixel array 110. Because each microlens 121 does not need to
have a large angle of view so as to cover the entire display
surface of the pixel array 110, the microlens 121 can be formed as
a convex lens of a practical size.
[0250] However, even when the user observes a virtual image
optically generated by each microlens 121 of the microlens array
120 in a state in which a picture is simply displayed on the
display surface of the pixel array 110, the user cannot view the
picture normally. It is only necessary to control the display in
the pixel array 110 using a method similar to a general light-ray
reproduction technology so that the picture can be observed as an
integral picture continuously when the display surface of the pixel
array 110 is observed from the predetermined position through the
microlens array 120 so as to allow the user to observe a normal
picture. That is, each pixel 111 of the pixel array 110 is driven
so that light rays are emitted from the microlenses 121 to the
user's pupil so that pictures to be visually recognized by the user
through the microlenses 121 of the microlens array 120 are provided
as a continuous and integral display.
[0251] Specifically, in the picture processing, it is only
necessary to control light emitted from each microlens 121 so that
the user can observe a virtual image of a continuous and integral
picture. At that time, the position of the virtual image in the
picture processing is adjusted to be equivalent to the virtual
image generation position determined from the hardware
configuration of the microlens 121. Thereby, the picture resolved
by the microlens 121 is provided as a continuous picture to the
user.
[0252] A result obtained by the present inventors examining whether
it is possible to implement technology for executing visual acuity
compensation while keeping the size dp of the pixel 111 at a
predetermined size in a device configuration similar to that of the
display device 10 illustrated in FIG. 10 has been described above.
As described above, in the device configuration similar to that of
the display device 10 illustrated in FIG. 10, it is possible to
compensate for the visual acuity of the user according to a
technique different from that of the above-described first
embodiment by optically generating a virtual image of a picture on
the display surface of the pixel array 110 by each microlens 121 of
the microlens array 120, generating a virtual image using a method
similar to light-ray reproduction so that the picture can be
observed as a continuous and integral picture when the display
surface of the pixel array 110 is observed through the microlens
array 120 from a predetermined position, and making virtual image
generation positions of the two virtual images equivalent.
[0253] According to this technique, because a virtual image is
optically generated by the microlens 121, it is not necessary to
set the sampling region 207 to a small region for visual acuity
compensation. Consequently, it is unnecessary to consider the
above-described condition 1. Also, because the resolution of the
display device 10 can be determined in accordance with the
magnification in the microlens 121 instead of the pitch of the
microlenses 121, it is also unnecessary to consider the
above-described condition 2.
[0254] Accordingly, according to this technique, it is possible to
perform visual acuity compensation without decreasing the size dp
of the pixel 111, in contrast to the first embodiment.
Consequently, for example, a display (pixel array) which is
generally widely used can be used as the pixel array 110 as it is
and it is possible to configure a display device without increasing
the manufacturing costs.
[0255] However, in this technique, the virtual image generation
position can be determined in hardware in accordance with a
distance between the microlens 121 and the display surface of the
pixel array 110 (that is, the lens inter-pixel distance DXL) and
the focal length f of the microlens 121. Accordingly, while there
is an advantage in that it is unnecessary to decrease the size dp
of the pixel 111 in the second embodiment, there is a disadvantage
in that convenience for the user is decreased as compared with the
first embodiment in which the virtual image generation position can
be arbitrarily changed. Whether the technique of the first
embodiment or the technique of the second embodiment is used may be
appropriately determined in accordance with a situation and/a field
of application.
3-2. Device Configuration
[0256] The configuration of the display device according to the
second embodiment will be described with reference to FIG. 30. FIG.
30 is a diagram illustrating an example of the configuration of the
display device according to the second embodiment.
[0257] Referring to FIG. 30, the display device 40 according to the
second embodiment includes a pixel array 110 in which a plurality
of pixels 111 are two-dimensionally arranged, a microlens array 120
provided on the display surface 115 of the pixel array 110 and a
control unit 430 that controls the driving of each pixel 111 of the
pixel array 110. Because the configurations of the pixel array 110
and the microlens array 120 are similar to the configurations of
these members in the display device 10 illustrated in FIG. 10,
detailed description thereof will be omitted here.
[0258] However, in the first embodiment, the distance between the
pixel array 110 and the microlens array 120 is set to be longer
than the focal length of each microlens 121 of the microlens array
120 to handle a real image. On the other hand, the pixel array 110
and the microlens array 120 are arranged so that the distance
between the pixel array 110 and the microlens array 120 is smaller
than the focal length of each microlens 121 of the microlens array
120 to optically generate a virtual image by each microlens 121 in
the second embodiment.
[0259] Also, as described above, in the first embodiment, the pixel
array 110 and the microlens array 120 need to be designed to
satisfy all of the above-described conditions 1 to 4. Accordingly,
the size dp of the pixel 111 and/or the pitch of the microlenses
121 tend(s) to be relatively small. On the other hand, in the
second embodiment, conditions 1 and 2 among conditions 1 to 4 need
not be considered. Accordingly, the size dp of the pixel 111 may be
larger than that of the first embodiment and may be equivalent to,
for example, that in a widely used general-purpose display.
[0260] However, also in the second embodiment, the pixel array 110
and the microlens array 120 are designed to satisfy conditions 3
and 4. That is, in the display device 40, the size dp of the pixel
111, the virtual image depth DIL, and the lens inter-pixel distance
DXL can be set to satisfy the predetermined resolution. Also, in
the display device 40, as in a case in which the irradiation state
of light with respect to the sampling region 207 in the first
embodiment is iterated in the predetermined cycle .lamda., the
irradiation state of light emitted from each microlens 121 of the
microlens array 120 is iterated in units larger than the maximum
pupil diameter of the user. Also in the second embodiment, the
pitch of the microlenses 121 and the lens inter-pixel distance DXL
can be set so that the iteration cycle at that time satisfies the
iteration cycle .lamda. determined by a technique similar to the
technique described in the above (2-2-3-2. Iteration cycle of
irradiation state of sampling region). That is, the iteration cycle
.lamda. of the irradiation state of the light can be set to be
larger than a pupil distance of the user. The iteration cycle
.lamda. of the irradiation state of the light can be set so that a
value obtained by multiplying the iteration cycle .lamda. by an
integer is substantially equal to the pupil distance of the
user.
[0261] Also, in the second embodiment, it is desirable that the
size of the region of the pixel array 110 visually recognized
through one microlens 121 be a size of an integer multiple of a
small region including RGB pixels of the pixel array 110. Although
different parts of the pixel array 110 are visually recognized
through one microlens 121 in accordance with the movement of the
viewpoint of the user, a color balance of the overall pixel array
110 visually recognized through one microlens 121 is not lost, and
the overall color balance can be made constant as a result, if such
a condition is satisfied.
[0262] The control unit 430 includes a processor such as a CPU, a
DSP, or the like, and operates in accordance with a predetermined
program, thereby controlling the driving of each pixel 111 of the
pixel array 110. The control unit 430 has a light-ray information
generating unit 431 and a pixel driving unit 432 as its functions.
Here, the functions of the light-ray information generating unit
431 and the pixel driving unit 432 correspond to those in which
some of functions of the light-ray information generating unit 131
and the pixel driving unit 132 in the display device 10 illustrated
in FIG. 10 are changed. Hereinafter, in terms of the control unit
430, the description of matters repeated from the control unit 130
of the display device 10 will be omitted and differences from the
control unit 130 will mainly be described.
[0263] The light-ray information generating unit 431 generates
light-ray information for driving each pixel 111 of the pixel array
110 on the basis of the picture information and the virtual image
position information. Here, as in the first embodiment, the picture
information is two-dimensional picture information presented to the
user. However, the virtual image position information is not
arbitrarily set as in the first embodiment, but is information
about a predetermined virtual image generation position determined
in accordance with the lens inter-pixel distance DXL and the focal
length of each microlens 121 of the microlens array 120.
[0264] Also, in the second embodiment, the light-ray information
generating unit 431 generates information indicating a light-ray
state in which pictures visually recognized through the microlenses
121 of the microlens array 120 are a continuous and integral
display on the basis of the picture information as light-ray
information. Also, at that time, the light-ray information
generating unit 431 generates the above-described light-ray
information so that a virtual image generation position related to
the continuous and integral display coincides with a virtual image
generation position determined in accordance with a positional
relationship between the pixel array 110 and the microlens array
120 based on the virtual image position information and optical
characteristics of the microlens 121. Further, in consideration of
the magnification in the microlens 121, the light-ray information
generating unit 431 may appropriately adjust the above-described
light-ray information so that the size of the picture finally
observed by the user becomes an appropriate size. The light-ray
information generating unit 431 provides the generated light-ray
information to the pixel driving unit 432.
[0265] Also, the picture information and the virtual image position
information may be transmitted from another device or may be stored
in advance in a storage device (not illustrated) provided in the
display device 40.
[0266] The pixel driving unit 432 drives each pixel 111 of the
pixel array 110 on the basis of the light-ray information. In the
second embodiment, each pixel 111 of the pixel array 110 is driven
on the basis of the light-ray information by the pixel driving unit
432 and therefore the light emitted from each microlens 121 is
controlled so that pictures visually recognized through each
microlens 121 of the microlens array 120 are a continuous and
integral display. Thereby, the user can recognize an optical
virtual image generated by each microlens 121 as a continuous and
integral picture.
[0267] As described above, the configuration of the display device
40 according to the second embodiment has been described with
reference to FIG. 30.
3-3. Display Control Method
[0268] A display control method to be executed in the display
device 40 according to the second embodiment will be described with
reference to FIG. 31. FIG. 31 is a flowchart illustrating an
example of a processing procedure of the display control method
according to the second embodiment. Also, each process illustrated
in FIG. 31 corresponds to each process to be executed by the
control unit 430 illustrated in FIG. 30.
[0269] Referring to FIG. 31, in the display control method
according to the second embodiment, light-ray information is first
generated on the basis of virtual image position information and
picture information (step S201). The virtual image position
information is information about a position (virtual image
generation position) at which a virtual image is generated in the
display device 40 illustrated in FIG. 30. In the second embodiment,
the virtual image position information is information about a
predetermined virtual image generation position determined in
accordance with a lens inter-pixel distance DXL and a focal length
of each microlens 121 of the microlens array 120. Further, the
picture information is two-dimensional picture information to be
presented to the user.
[0270] In the process shown in step S101, information indicating a
light-ray state in which pictures visually recognized through the
microlenses 121 of the microlens array 120 are a continuous and
integral display is generated as light-ray information on the basis
of the picture information. At that time, the above-described
light-ray information can be generated so that a virtual image
generation position related to the continuous and integral display
coincides with a virtual image generation position determined by a
positional relationship between the pixel array 110 and the
microlens array 120 based on the virtual image position information
and the optical characteristics of the microlens 121. Further, in
the process shown in step S101, the above-described light-ray
information may be appropriately adjusted so that the size of the
picture finally observed by the user becomes an appropriate size in
consideration of the magnification in the microlens 121.
[0271] Next, each pixel is driven so that the picture visually
recognized through each microlens 121 of the microlens array 120
becomes a continuous and integral display on the basis of the
light-ray information (step S203). As a result, the optical virtual
image generated by each microlens 121 is provided as a continuous
and integral picture to the user.
[0272] The display control method according to the second
embodiment has been described above.
3-4. Modified Example
[0273] As described above, according to the second embodiment, it
is possible to make the size dp of the pixel 111 relatively large.
However, when the above-described condition 3 is considered, it is
necessary to increase the lens inter-pixel distance DXL so as to
keep the resolution at a predetermined value when the size dp of
the pixel 111 is increased. Accordingly, while the size dp of the
pixel 111 can be increased in the display device 40, the lens
inter-pixel distance DXL may be increased and the size of the
device may be increased depending on the required resolution. Here,
as a modified example of the second embodiment, a method of
preventing such an increase in the size of the device by devising a
configuration for the microlens array 120 will be described.
[0274] As a lens system generally used as a telescopic lens, a lens
system called a telephoto type is known. In a telephoto type lens
system, it is possible to implement a light-ray state equivalent to
that of one convex lens located at a more remote position in a more
compact configuration by combining a convex lens and a concave
lens.
[0275] A telephoto type lens system will be described with
reference to FIG. 32. FIG. 32 is a diagram illustrating an example
of a configuration of a telephoto type lens system.
[0276] As illustrated in FIG. 32, a telephoto type lens system is
configured by combining a convex lens 823 and a concave lens 825.
As illustrated, in the telephoto type lens system, a main surface
827 of a coupling system is located farther away than the convex
lens 823 when viewed from the focus 829. That is, the focal length
f (a distance between the main surface 827 and the focus 829) is
longer than the distance from the focus 829 to the convex lens 823.
Here, if it is intended to implement the light-ray state
illustrated in FIG. 32 with one convex lens, the convex lens can be
located on the main surface 827. As described above, in the
telephoto type lens system, it is possible to implement a light-ray
state equivalent to that of one convex lens in a more compact
configuration.
[0277] In the present modified example, each microlens 121 of the
microlens array 120 illustrated in FIG. 30 includes such a
telephoto type lens system. That is, in the present modified
example, each microlens 121 of the microlens array 120 illustrated
in FIG. 30 includes a telephoto type lens system in which a convex
lens 823 and a concave lens 825 are combined. Specifically, the
microlens array 120 is formed by stacking a first microlens array
in which convex lenses 823 are arranged and a second microlens
array in which concave lenses 825 are arranged.
[0278] In this case, for example, as illustrated in FIG. 32, the
pixel array 110 can be arranged between the concave lens 825 and
the focus 829. For example, as illustrated in FIG. 30, when the
microlens array 120 is formed with only a lens array of one layer
including convex lenses, the distance between the pixel array 110
and the microlens array 120 can be relatively long (for example, a
distance d2 illustrated in FIG. 32) because the microlens array 120
needs to be arranged on the main surface 827 as described above in
order to implement the light-ray state illustrated in FIG. 32. On
the other hand, by configuring the microlens array 120 with the
telephoto type lens system as in the present modified example, it
is possible to implement the same light-ray state with a smaller
configuration, so that it is possible to further shorten the
distance between the pixel array 110 and the microlens array 120
(for example, a distance d1 illustrated in FIG. 32).
[0279] As described above, according to the present modified
example, in the configuration of the display device 40 illustrated
in FIG. 30, the microlens array 120 includes a telephoto type lens
system. Accordingly, the distance between the pixel array 110 and
the microlens array 120 can be further shortened and the display
device can be further downsized.
[0280] A modified example in which each microlens 121 of the
microlens array 120 includes a telephoto type lens system has been
described above as a modified example of the second embodiment.
[0281] Also, in addition to the modified examples, various modified
examples described in the first embodiment can also be applied to
the display device 40 according to the second embodiment.
Specifically, the configurations described in the above (2-5-3.
Dynamic control of irradiation state in accordance with pupil
position detection) and (2-5-4. Modified example in which pixel
array is implemented by printing material) may be applied to the
display device 40.
[0282] Also, the display device 40 according to the second
embodiment may be applied to devices similar to various application
examples for the display device 10 according to the above-described
first embodiment. Specifically, the display device 40 can be
applied to various devices described in the above (2-4-1.
Application to wearable device), the above (2-4-2. Application to
other mobile devices), the above (2-4-3. Application to electronic
loupe device) and (2-4-4. Application to in-vehicle display
device).
4. Configuration of Microlens Array
[0283] The configuration of the microlens array 120 in the
above-described first and second embodiments will be described in
more detail. Here, the configuration of the microlens array 120 in
the display device 40 according to the second embodiment will be
described as an example. However, the configuration of the
microlens array 120 described below can also be preferably applied
to the display device 10 according to the first embodiment and the
display device 20 according to the modified example.
[0284] In the display device 40, a shape of each microlens 121 on
the microlens array 120 can be designed in consideration of a
viewpoint of a user who views the display device 40. At this time,
in accordance with positional relationships between the left and
right eyes of the user and the microlens 121, it is necessary to
perform the design in consideration of the following two phenomena
because an angle formed between a light ray incident on the eyes of
the user from the pixels 111 of the pixel array 110 via the
microlenses 121 and the optical axis of the microlens 121 varies
greatly.
[0285] The two phenomena will be described with reference to FIG.
33. FIG. 33 is a diagram schematically illustrating positional
relationships between the positions of both eyes of the user who
observes the display device 40 and the microlenses 121 of the
microlens array 120. In FIG. 33, only three microlenses 121
arranged at positions D0, D1, and D2 among the microlenses 121
included in the microlens array 120 are representatively
illustrated. Also, a position EP.sub.L of the left eye and a
position EP.sub.R of the right eye of the user who is observing the
display device 40 from the position of a distance L from the
microlens array 120 are simulatively shown as spatial points.
[0286] For example, in the illustrated example, a case in which the
microlens 121 located at the position D2 in front of the left eye
of the user is viewed is considered. In this case, while an angle
between a straight line connecting the left eye and the microlens
121 (that is, a straight line connecting EP.sub.L and D2) and a
perpendicular line of the array surface of the microlens array 120
is substantially zero, an angle formed between a straight line
connecting the right eye and the microlens 121 (that is, a straight
line connecting EP.sub.R and D2) and a perpendicular line of the
array surface of the microlens array 120 is a non-zero angle. As an
example, if a distance L=150 (mm) and a distance D.sub.LR between
the left and right eyes is D.sub.LR=60 (mm), the angle is about 22
degrees.
[0287] That is, when viewed from the microlens 121, the right eye
and the left eye of the user exist in mutually different directions
(angles). In this manner, when the angular difference with respect
to the left and right eyes is large, the aberration increases as a
first phenomenon and favorable images are not formed on the left
and right eyes, that is, favorable display cannot be
implemented.
[0288] Also, as a second phenomenon, there is concern of occurrence
of vignetting. That is, when the microlens array 120 is formed by
stacking a plurality of microlens array surfaces (for example, when
the microlens array 120 is formed by laminating a plurality of
microlens arrays as described in the above (3-4. Modified example),
when a microlens array is provided on both the front and back
surfaces of the microlens array 120, or the like), so-called
vignetting in which light passing through the first microlens array
surface does not pass through a desired microlens surface of the
second microlens array surface may occur. For example, when the
angle difference with respect to the left and right eyes viewed
from the microlens 121 is large like at D2, normal light rays
without vignetting are incident on the left eye, but vignetting for
the right eye may occur and light rays may not be incident
normally. When such a situation occurs, problems such as hindrance
of normal display and darkening of the picture may occur.
[0289] Because generation of aberration and vignetting can hinder
favorable display for the user as described above, it is preferable
that each microlens 121 of the microlens array 120 be designed to
decrease the occurrence of aberration and vignetting. At this time,
for example, the microlens array 120 may be configured by
two-dimensionally arranging microlenses 121 of the same shape.
However, it is extremely difficult to design the shape of each
microlens 121 so that favorable display with less aberration and
vignetting is implemented in all combinations of positional
relationships between the left and right eyes of the user and the
microlens 121 while using microlenses 121 having the same shape.
The occurrence of aberration and vignetting is considered to be
more conspicuous when a display device 40 with a larger screen is
observed from a comparatively short distance. In this case, the
angular difference with respect to the left and right eyes of the
user as viewed from the microlens 121 becomes larger. In such a
case, designing the microlenses 121 will be more difficult.
[0290] Therefore, in the present disclosure, it is preferable to
assume the positions (viewpoints) of the eyes of the user with
respect to the display device 40 being at predetermined positions
and the shape of each microlens 121 being designed so that
favorable image formation is implemented in accordance with the
positional relationship between the viewpoint and each microlens
121. That is, the plurality of microlenses 121 are configured to
have shapes different from one another so that favorable display
can be implemented in consideration of the viewpoint of the user in
accordance with the position of each microlens 121 within the array
surface of the microlens array 120. Thereby, it is possible to
provide the user with more preferable display than when all the
microlenses 121 have the same shape.
[0291] Also, ideally, it is preferable to optimally design all
microlenses 121 on the microlens array 120 depending on their
positions. However, if the number of steps or the like involved in
design is considered, such a design method is not necessarily
realistic. Accordingly, some points (hereinafter also referred to
as design points) for optimum design of the microlenses 121 are set
on the microlens array and the shape is optimally designed so that
the degree of aberration and the occurrence of vignetting are
minimized for the microlenses 121 located at these design points.
With respect to the microlenses 121 located at positions other than
the design points, the shape is designed using the design results
for the microlenses 121 located at the design points. Specifically,
for example, because trends in change in a shape of the lenses
depending on the position on the array surface of the microlens
array 120 can be ascertained from the results of the optimum design
of microlenses 121 at a plurality of design points, it is simply
necessary to design microlenses 121 other than those at the design
points on the basis of these trends.
[0292] The above-described method of designing the microlens 121
will be described in more detail with reference to FIG. 34. FIG. 34
is an explanatory diagram illustrating the method of designing the
microlens 121. In FIG. 34, the microlens array 120 of the display
device 40 is illustrated and the design points D0 to D6 set on the
microlens array 120 are illustrated. Also, viewpoints (a left eye
position EP.sub.L and a right eye position EP.sub.R) of the user
who views the display device 40 (that is, the microlens array 120)
are simulatively shown as spatial points.
[0293] An example of a specific microlens array 120 and design
points D0 to D6 for which the present inventors actually designed
the microlenses 121 is illustrated in FIG. 34. In this design
example, the display device 40 is assumed to be applied to a
display screen of a smartphone and the microlens array 120 has a
rectangular array surface of 126 (mm) in length and 80 (mm) in
width. Also, hereinafter, for description, a vertical direction of
the microlens array 120 in FIG. 34 is also referred to as a y-axis
direction and a horizontal direction is referred to as a x-axis
direction. FIG. 33 described above corresponds to a cross-sectional
view of the microlens array 120 illustrated in FIG. 34 taken along
the line A-A parallel to the x-axis.
[0294] Also, in the design example, the positions EP.sub.L and
EP.sub.R of the left and right eyes of the user are set at the
center of the microlens array 120 in the y-axis direction. EP.sub.L
and EP.sub.R are set at positions symmetrical with respect to the
center of the array surface of the microlens array 120 in the
x-axis direction and the distance D.sub.LR between the left and
right eyes (that is, the distance between EP.sub.L and EP.sub.R) is
set to 60 (mm) in consideration of a general pupil distance PD.
Although not clearly illustrated in FIG. 34, EP.sub.L and EP.sub.R
do not exist on the same plane as the microlens array 120, and are
set at positions separated by predetermined distances from the
microlens array 120 in a direction perpendicular to the drawing
sheet in consideration of the user's viewing distance. In this
specific example, a distance between the microlens array 120 and
each of EP.sub.L and EP.sub.R in the direction perpendicular to the
drawing sheet is 150 (mm).
[0295] Also, in the design example, seven design points D0 to D6
are set at the illustrated positions. Also, as illustrated, all the
design points D0 to D6 exist in the area corresponding to the
fourth quadrant of the array surface of the microlens array 120,
but this is because a result of optimum design at a point
corresponding to a design point in another quadrant can also be
easily obtained by appropriately using a result of optimum design
if the optimum design of a lens at a design point in one quadrant
is performed because the positions EP.sub.L and EP.sub.R of the
left and right eyes of the user are set symmetrically with respect
to the center of the array surface of the microlens array 120. Of
course, depending on positional relationships between the microlens
array 120, EP.sub.L, and EP.sub.R, design points may be provided to
be distributed across the entire surface of the array surface.
[0296] For the microlenses 121 located at the design points D0 to
D6 set as described above, the optimum design of the shape is
performed so that the aberration for the left and right eyes
existing at the positions EP.sub.L and EP.sub.R is decreased.
Specifically, the shape of each microlens 121 is designed so that
favorable image formation with less aberration (that is, in both
right and left eyes) in both EP.sub.L and EP.sub.R is obtained in
consideration of a three-dimensional positional relationship
between EP.sub.L and EP.sub.R (that is, left and right eyes) for
each of the microlenses 121 located at the design point D0 to D6.
When the microlens array 120 is configured by stacking a plurality
of microlens array surfaces, the optimum design of the shape of
each of the microlenses 121 on the plurality of microlens array
surfaces located at the design points D0 to D6 is performed so that
vignetting is further decreased in both EP.sub.L and EP.sub.R in
consideration of three-dimensional positional relationships with
EP.sub.L and EP.sub.R.
[0297] When the optimum design is made for the microlens 121
located at each of the design points D0 to D6, from the design
results, trends in change in a shape of the microlenses 121
depending on the position on the array surface of the microlens
array 120 can be ascertained. For the microlenses 121 other than
those located at the design points D0 to D6, the shape is designed
on the basis of these trends. Thereby, the shape of each microlens
121 is designed. Each of the designed microlenses 121 preferably
has an aspheric shape.
[0298] The method of designing the microlens 121 has been described
above. By designing the shape of each microlens 121 on the basis of
the position of the viewpoint of the user and the position of each
microlens 121 within the array surface of the microlens array 120,
more preferable display can be provided to the user. Also, in the
above-described design example, the shape of the microlenses 121
gradually changes in accordance with the position within the array
surface of the microlens array 120, but the method of designing the
microlens 121 is not limited to this example. For example, the
surface of the microlens array 120 may be divided into a plurality
of regions and the shape of the microlenses 121 may be designed for
each region. According to this method, although the accuracy of the
optimum design of each microlens 121 may be slightly lowered, the
entire microlens array 120 can be designed more simply than when
the microlenses 121 are individually designed.
[0299] Also, the reason why the number of design points in the
above-described design example is seven is that trends in change in
the shape of the microlenses 121 depending on the position on the
array surface of the microlens array 120 can be ascertained through
the optimum design of the microlenses 121 at the seven design
points D0 to D6 if the microlens array 120 has a degree of size as
illustrated, as a result of examination by the present inventors.
Because the size of the microlens array 120 changes in accordance
with a device to which the display device 40 is applied, the
positions of design points and the number of design points can be
appropriately set so that the trends in change in the shape of the
microlenses can be ascertained in accordance with the size of the
microlens array 120.
[0300] Further, because the display device 40 is assumed to be
applied to the display screen of a smartphone as described above
for the setting of EP.sub.L and EP.sub.R in the above-described
design example, an example of the positional relationship between
the user and the display surface when a smartphone is used is
assumed. When a device to which the display device 40 is applied is
different, the positions of EP.sub.L and EP.sub.R may be
appropriately set in consideration of the general positional
relationship between the user and the display screen when the
device is used. Also, the position of the viewpoint (that is, the
combination of the positions of EP.sub.L and EP.sub.R) is not
limited to one position. For example, in a smartphone, both a usage
mode in which the user views the display of the display screen in
the vertical direction (that is, a usage mode in which the
smartphone is used in the direction of the microlens array 120
illustrated in FIG. 33) and a usage mode in which the user views
the display of the display screen in the horizontal direction (that
is, a usage mode in which the smartphone is used after the
microlens array 120 illustrated in FIG. 33 is rotated by 90 degrees
around a rotation axis in a direction perpendicular to the drawing
sheet) may be considered. Thus, although only the positions of
EP.sub.L and EP.sub.R when the display screen is set in the
vertical direction are considered in the above-described design
example, the optimum design of the microlenses 121 at the design
points D0 to D6 may be performed in consideration of the positions
of EP.sub.L and EP.sub.R when the display screen is set in the
horizontal direction in addition thereto.
[0301] Here, in the design of the microlenses depending on the
position of the viewpoint, the shape of each microlens 121 is
designed in the above-described design example. However, the method
of designing the microlenses depending on the position of the
viewpoint is not limited to this example. For example, when the
microlens array 120 is configured by stacking a plurality of
microlens array surfaces, a positional relationship between
microlenses 121 among the plurality of microlens array surfaces
and/or a relationship between the number of microlenses 121 may
also be appropriately designed instead of designing the shape of
the microlenses 121 as described above or in addition to designing
the shape of the microlenses 121 as described above.
[0302] For example, an example of a configuration in which a
positional relationship between microlenses 127 and 129 of
two-layer microlens arrays 126 and 128 in accordance with a
position of a viewpoint of the user is shifted in the microlens
array 120 including the two-layer microlens arrays 126 and 128 is
illustrated in FIG. 35. As described in the above (3-4. Modified
example), when the microlens array 120 includes the two-layer
microlens arrays 126 and 128, the microlens array 120 can be
assumed to be configured normally so that the position of the
boundary between the microlenses 127 in the first-layer microlens
array 126 and the position of the boundary between the microlenses
129 in the second-layer microlens array 128 substantially coincide.
The upper portion ((a) in FIG. 35) of FIG. 35 schematically
illustrates the configuration. In this case, the position of the
boundary between the microlenses 127 and 129 is designed by
assuming that the light from the pixels 111 of the pixel array 110
passes through the microlenses 127 and 129 overlapping each other
and is incident on the eyes of the user.
[0303] Here, a case in which the direction from either the left or
right eye of the user towards the microlenses 127 and 129 (that is,
the direction of the visual line at either the left or the right of
the user) is inclined by a predetermined angle from the optical
axis of the microlenses 127 and 129 as indicated by an arrow in
FIG. 35 is considered. The arrow illustrated in FIG. 35 corresponds
to, for example, a case in which the microlenses 127 and 129
located at the position D2 illustrated in FIG. 33 are viewed with
the right eye (EP.sub.R). In this case, there is a high possibility
that light from the pixel 111 will not pass through the
corresponding microlenses 127 and 129 normally, that is, vignetting
will occur.
[0304] Therefore, when a microlens depending on the position of the
viewpoint is designed, the positional relationship between the
microlenses 127 and 129 in the two-layer microlens arrays 126 and
128 may be appropriately adjusted so that vignetting is less likely
to occur as illustrated in the lower portion of FIG. 35 ((b) in
FIG. 35). Specifically, the position of the boundary between the
microlenses 127 within a plane horizontal to the array surface in
the first-layer microlens array 126 and the position of the
boundary between the microlenses 129 within a plane horizontal to
the array surface in the second-layer microlens array 128 may be
appropriately shifted so that vignetting is less likely to occur in
accordance with the position of the viewpoint of the user. In the
illustrated example, the boundary position of the microlenses 129
of the second-layer microlens array 128 within the plane is shifted
to correspond to the direction of the visual line of the user
indicated by the arrow in FIG. 35. As described above, the
microlens array 120 can be configured so that vignetting is less
likely to occur in accordance with the position of the user's
viewpoint by configuring the microlens array 120 so that the
position of the boundary between the microlenses 127 in the
first-layer microlens array 126 and the position of the boundary
between the microlenses 129 in the second-layer microlens array 128
are different from each other.
[0305] When this configuration is applied to the entire microlens
array 120, it is only necessary to design the positional
relationship of the optimum boundaries of the two-layer microlens
arrays 126 and 128 for a plurality of design points D0 to D6 within
the array surface of the microlens array 120 as illustrated in, for
example, FIG. 34. It is only necessary to acquire a distribution of
shift amounts of the microlens arrays 126 and 128 depending on
positions within the array surface of the microlens array 120 from
the design results at the design points D0 to D6 and calculate
shift amounts of the microlens arrays 126 and 128 at positions
other than design points on the basis of the distribution.
Alternatively, the array surface of the microlens array 120 may be
divided into a plurality of regions and the shift amounts of the
microlens arrays 126 and 128 may be determined for each region
using the above-described distribution.
[0306] Also, for example, FIG. 36 is a diagram illustrating an
example of a configuration in which the number of microlenses to
which the two-layer microlens arrays 126 and 128 mutually
correspond changes in accordance with the position of the viewpoint
of the user in the microlens array 120 including the two-layer
microlens arrays 126 and 128. As described in the above (3-4.
Modified example), when the microlens array 120 includes the
two-layer microlens arrays 126 and 128, the microlens array 120 can
be assumed to be configured so that the microlenses 127 in the
first-layer microlens array 126 and the microlenses 129 in the
second-layer microlens array 128 have one-to-one correspondence.
The upper portion ((a) in FIG. 36) of FIG. 36 schematically
illustrates this configuration.
[0307] Here, a case in which the directions from the left and right
eyes of the user to the microlenses 127 and 129 (that is, the
directions of the visual lines at the left and right eyes of the
user) are different directions in the left and right eyes as
indicated by arrows in FIG. 36 is considered. The arrows
illustrated in FIG. 36 correspond to, for example, a case in which
the microlenses 127 and 129 located at the position D0 illustrated
in FIG. 33 are viewed with both eyes (EP.sub.L and EP.sub.R). In
this case, it may be difficult to design both the shapes of the
microlenses 127 and 129 so that the shapes can correspond to both
the visual lines from the left and right eyes.
[0308] Therefore, when the optimum design of the microlenses
depending on the position of the viewpoint is performed, the
microlens array 120 may be configured so that the two microlenses
129a and 129b in the second-layer microlens array 128 correspond to
one microlens 127 in the first-layer microlens array 126 as
illustrated in the lower portion of FIG. 36 ((b) in FIG. 36). That
is, the microlenses 129 of the other microlens array 128
corresponding to one microlens 127 of one microlens array 126 may
be appropriately divided in accordance with a difference between
the directions of the visual lines from the plurality of
viewpoints. One microlens 129a obtained through the division
corresponds to one viewpoint (for example, the left eye) and the
other microlens 129b corresponds to the other viewpoint (for
example, the right eye). At this time, the shapes of the
microlenses 129a and 129b obtained by the division may be
appropriately designed to obtain favorable display. In this manner,
the microlens array 120 is configured so that the plurality of
microlenses 129a and 129b in the second-layer microlens array 128
correspond to one microlens 127 of the first-layer microlens array
126, so that the microlens array 120 can be configured to prevent
aberration from occurring in accordance with the viewpoint of the
user. Also, in the illustrated example, one type of microlens 129
in the second-layer microlens array 128 are divided into two
microlenses 129a and 129b, but the number of divisions of the
microlenses 129 may be larger. That is, a plurality of microlenses
may be formed in the second-layer microlens array 128 for one
microlens 127 in the first-layer microlens array 126. Also, the
microlenses 127 of the first-layer microlens array 126 may be
divided. That is, a plurality of microlenses may be formed in the
first-layer microlens array 126 with respect to one type of
microlens 129 in the second-layer microlens array 128.
[0309] When this configuration is applied to the entire microlens
array 120, it is only necessary to design the number of optimal
microlenses 127 and 129 in the two-layer microlens arrays 126 and
128 and the arrangement of the optimal microlenses 127 and 129 at,
for example, a plurality of design points D0 to D6 within the array
surface of the microlens array 120 as illustrated in FIG. 34. It is
only necessary to acquire the number of microlenses 127 and 129
within the array surface of the microlens array 120 and a
distribution of arrangements from the design results at the design
points D0 to D6 and design the number of microlenses 127 and 129
and the arrangements of microlenses 127 and 129 at positions other
than design points on the basis of the distribution. Alternatively,
the array surface of the microlens array 120 may be divided into a
plurality of regions and the number of microlenses 127 and 129 and
the arrangements of microlenses 127 and 129 may be determined for
each region using the above-described distribution.
[0310] Also, although a case in which the microlens array 120 is
configured by stacking a plurality of microlens arrays has been
described in the examples illustrated in FIGS. 35 and 36, the
configuration of the microlens array 120 to which the
above-described design method of shifting the boundary between the
microlenses and the above-described design method of dividing the
microlenses can be applied is not limited to this example. For
example, even for a microlens array 120 including one layer (one
piece) having microlens array surfaces formed on the front and back
sides or a microlens array 120 having three or more microlens array
surfaces, design methods thereof may be applied in a similar
type.
[0311] As described above, by designing the microlens array 120 in
consideration of the viewpoint of the user, aberration and
vignetting can be decreased in the entire screen and the effect of
visual acuity compensation can be obtained in a more appropriate
state. Also, as compared with when the microlens array 120 is
formed by microlenses 121 having the same shape, it is possible to
relax restriction requirements of design. In some cases, because it
is also possible to decrease the number of layers of microlens
arrays included in the microlens array 120 for implementing similar
performance, a decrease in manufacturing costs can be implemented
as a result.
[0312] Also, if the above-described design method is used in
reverse, it is also possible to configure the microlens array 120
so that it is difficult to view a display from a predetermined
viewpoint, that is, so that the aberration becomes large at a
predetermined viewpoint and/or the occurrence of vignetting becomes
conspicuous and the display becomes unclear. According to this
configuration, prying from the surroundings can be suitably
prevented.
5. Supplement
[0313] The preferred embodiment(s) of the present disclosure
has/have been described above with reference to the accompanying
drawings, whilst the present disclosure is not limited to the above
examples. A person skilled in the art may find various alterations
and modifications within the scope of the appended claims, and it
should be understood that they will naturally come under the
technical scope of the present disclosure.
[0314] Further, the effects described in this specification are
merely illustrative or exemplified effects, and are not limitative.
That is, with or in the place of the above effects, the technology
according to the present disclosure may achieve other effects that
are clear to those skilled in the art from the description of this
specification.
[0315] Also, the above-described device configurations of the
display devices 10, 20, and 40 are not limited to the examples
illustrated in FIGS. 10, 28, and 30. For example, the functions of
the control units 130, 230, and 430 may not necessarily be
integrally mounted in one device. The functions of the control
units 130, 230, and 430 may be distributed and mounted on a
plurality of devices (for example, a plurality of processors) and
the plurality of devices may be connected to communicate with one
another so that the functions of the above-described control units
130, 230, and 430 may be implemented.
[0316] Also, a computer program for implementing the functions of
the control units 130, 230, and 430 as described above can be
manufactured and mounted on a personal computer or the like. Also,
it is possible to provide a computer-readable recording medium in
which such a computer program is stored. The recording medium is,
for example, a magnetic disk, an optical disc, a magneto-optical
disc, a flash memory, or the like. Also, the computer program may
be distributed via, for example, a network, without using a
recording medium.
[0317] Additionally, the present technology may also be configured
as below.
(1)
[0318] A display device including:
[0319] a pixel array; and
[0320] a microlens array provided on a display surface side of the
pixel array and having lenses arranged at a pitch larger than a
pixel pitch of the pixel array,
[0321] wherein the microlens array is arranged so that each lens of
the microlens array generates a virtual image of display of the
pixel array on a side opposite to a display surface of the pixel
array, and
[0322] light emitted from each lens of the microlens array is
controlled so that pictures visually recognized through lenses of
the microlens array become a continuous and integral display by
controlling the light from each pixel of the pixel array.
(2)
[0323] The display device according to (1), wherein an irradiation
state of light emitted from each lens of the microlens array is
periodically iterated in units larger than a maximum pupil diameter
of a user.
(3)
[0324] The display device according to (2), wherein an iteration
cycle of the irradiation state of the light is larger than a pupil
distance of the user.
(4)
[0325] The display device according to (2) or (3), wherein a value
obtained by multiplying an iteration cycle of the irradiation state
of the light by an integer is substantially equal to a pupil
distance of the user.
(5)
[0326] The display device according to any one of (2) to 4, wherein
light emitted from each lens of the microlens array is controlled
so that a pupil of the user is not located on a boundary of
iteration of the irradiation state of the light in accordance with
a position of the pupil of the user.
(6)
[0327] The display device according to any one of (1) to (5),
wherein each lens of the microlens array includes a telephoto type
lens system in which a convex lens and a concave lens are
combined.
(7)
[0328] The display device according to any one of (1) to (6),
further including:
[0329] a movable mechanism configured to make a distance between
the pixel array and the microlens array variable.
(8)
[0330] The display device according to any one of (1) to (7),
wherein light emitted from each lens of the microlens array is
controlled so that a picture captured by an imaging device is
visually recognized as an integral display through each lens of the
microlens array.
(9)
[0331] The display device according to any one of (1) to (7),
wherein the pixel array includes a plurality of printed pixels.
(10)
[0332] The display device according to any one of (1) to (9),
wherein each lens of the microlens array has a surface shape
differing in accordance with a position of the lens within an array
surface.
(11)
[0333] The display device according to any one of (1) to (10),
[0334] wherein the microlens array is configured by stacking a
plurality of microlens array surfaces, and
[0335] one microlens array surface and at least one other microlens
array surface among the plurality of microlens array surfaces are
formed so that boundary positions between lenses within surfaces
horizontal to the array surfaces are different from each other.
(12)
[0336] The display device according to any one of (1) to (11),
[0337] wherein the microlens array is configured by stacking a
plurality of microlens array surfaces, and
[0338] one microlens array surface and at least one other microlens
array surface among the plurality of microlens array surfaces are
formed so that a plurality of lenses in the at least one other
microlens array correspond to one lens of the one microlens array
surface.
(13)
[0339] The display device according to any one of (10) to (12),
wherein each lens of the microlens array has an aspheric shape.
(14)
[0340] The display device according to any one of (10) to (13),
wherein each lens of the microlens array is designed so that
display is unclear at a position of a predetermined viewpoint of a
user.
(15)
[0341] The display device according to any one of (10) to (14),
wherein the display device is used as an in-vehicle display device
on which driving support information is displayed.
(16)
[0342] A display control method including:
[0343] controlling light emitted from each lens of a microlens
array so that pictures visually recognized through lenses of the
microlens array become a continuous and integral display by
controlling light from each pixel of a pixel array, the microlens
array being provided on a display surface side of the pixel array
and having lenses arranged at a pitch larger than a pixel pitch of
the pixel array,
[0344] wherein the microlens array is arranged so that each lens of
the microlens array generates a virtual image of display of the
pixel array on a side opposite to a display surface of the pixel
array.
REFERENCE SIGNS LIST
[0345] 10, 20, 40 display device [0346] 30 wearable device [0347]
110 pixel array [0348] 111 pixel [0349] 120 microlens array [0350]
121 microlens [0351] 130, 230, 430 control unit [0352] 131, 431
light-ray information generating unit [0353] 132, 432 pixel driving
unit [0354] 150 virtual image surface [0355] 231 pupil position
detecting unit [0356] 310, 320, 333 first shielding plate (aperture
film) [0357] 311, 321 opening
* * * * *